Selecting storage units in a dispersed storage network

ABSTRACT

A method begins by a processing module of a dispersed storage network (DSN) receiving, from a requesting device, a request to retrieve a unique copy of a data file, where the data file is divided into a plurality of data segments, where a data segment is dispersed storage error encoded to produce a set of encoded data slices, and where the plurality of sets of encoded data slices is stored in a set of storage units of the DSN. The method continues with the processing module determining a retrieval combination code from the request and interpreting the retrieval combination code to identify a sub-set of storage units. The method continues with the processing module sending read requests to the sub-set of storage units and when the decode threshold number of encoded data slices is received, decoding the decode threshold number of encoded data slices to recover the data segment.

CROSS REFERENCE TO RELATED PATENTS

The present U.S. Utility patent application claims priority pursuant to 35 U.S.C. §119(e) to U.S. Provisional Application No. 62/154,867, entitled “AUTHORIZING A SLICE ACCESS REQUEST IN A DISPERSED STORAGE NETWORK,” filed Apr. 30, 2015, which is hereby incorporated herein by reference in its entirety and made part of the present U.S. Utility patent application for all purposes.

The present U.S. Utility patent application also claims priority pursuant to 35 U.S.C. §120 as a continuation-in-part of U.S. Utility application Ser. No. 12/903,212, entitled “DIGITAL CONTENT RETRIEVAL UTILIZING DISPERSED STORAGE,” filed Oct. 13, 2010, which claims priority pursuant to 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/290,632, entitled “DIGITAL CONTENT DISTRIBUTED STORAGE,” filed Dec. 29, 2009, all of which are hereby incorporated herein by reference in their entirety and made part of the present U.S. Utility patent application for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

NOT APPLICABLE

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

NOT APPLICABLE

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to computer networks and more particularly to dispersed storage of data and distributed task processing of data.

2. Description of Related Art

Computing devices are known to communicate data, process data, and/or store data. Such computing devices range from wireless smart phones, laptops, tablets, personal computers (PC), work stations, and video game devices, to data centers that support millions of web searches, stock trades, or on-line purchases every day. In general, a computing device includes a central processing unit (CPU), a memory system, user input/output interfaces, peripheral device interfaces, and an interconnecting bus structure.

As is further known, a computer may effectively extend its CPU by using “cloud computing” to perform one or more computing functions (e.g., a service, an application, an algorithm, an arithmetic logic function, etc.) on behalf of the computer. Further, for large services, applications, and/or functions, cloud computing may be performed by multiple cloud computing resources in a distributed manner to improve the response time for completion of the service, application, and/or function. For example, Hadoop is an open source software framework that supports distributed applications enabling application execution by thousands of computers.

In addition to cloud computing, a computer may use “cloud storage” as part of its memory system. As is known, cloud storage enables a user, via its computer, to store files, applications, etc., on an Internet storage system. The Internet storage system may include a RAID (redundant array of independent disks) system and/or a dispersed storage system that uses an error correction scheme to encode data for storage.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of a distributed computing system in accordance with the present invention;

FIG. 2 is a schematic block diagram of an embodiment of a computing core in accordance with the present invention;

FIG. 3 is a diagram of an example of a distributed storage and task processing in accordance with the present invention;

FIG. 4 is a schematic block diagram of an embodiment of an outbound distributed storage and/or task (DST) processing in accordance with the present invention;

FIG. 5 is a logic diagram of an example of a method for outbound DST processing in accordance with the present invention;

FIG. 6 is a schematic block diagram of an embodiment of a dispersed error encoding in accordance with the present invention;

FIG. 7 is a diagram of an example of a segment processing of the dispersed error encoding in accordance with the present invention;

FIG. 8 is a diagram of an example of error encoding and slicing processing of the dispersed error encoding in accordance with the present invention;

FIG. 9 is a diagram of an example of grouping selection processing of the outbound DST processing in accordance with the present invention;

FIG. 10 is a diagram of an example of converting data into slice groups in accordance with the present invention;

FIG. 11 is a schematic block diagram of an embodiment of a DST execution unit in accordance with the present invention;

FIG. 12 is a schematic block diagram of an example of operation of a DST execution unit in accordance with the present invention;

FIG. 13 is a schematic block diagram of an embodiment of an inbound distributed storage and/or task (DST) processing in accordance with the present invention;

FIG. 14 is a logic diagram of an example of a method for inbound DST processing in accordance with the present invention;

FIG. 15 is a diagram of an example of de-grouping selection processing of the inbound DST processing in accordance with the present invention;

FIG. 16 is a schematic block diagram of an embodiment of a dispersed error decoding in accordance with the present invention;

FIG. 17 is a diagram of an example of de-slicing and error decoding processing of the dispersed error decoding in accordance with the present invention;

FIG. 18 is a diagram of an example of a de-segment processing of the dispersed error decoding in accordance with the present invention;

FIG. 19 is a diagram of an example of converting slice groups into data in accordance with the present invention;

FIG. 20 is a diagram of an example of a distributed storage within the distributed computing system in accordance with the present invention;

FIG. 21 is a schematic block diagram of an example of operation of outbound distributed storage and/or task (DST) processing for storing data in accordance with the present invention;

FIG. 22 is a schematic block diagram of an example of a dispersed error encoding for the example of FIG. 21 in accordance with the present invention;

FIG. 23 is a diagram of an example of converting data into pillar slice groups for storage in accordance with the present invention;

FIG. 24 is a schematic block diagram of an example of a storage operation of a DST execution unit in accordance with the present invention;

FIG. 25 is a schematic block diagram of an example of operation of inbound distributed storage and/or task (DST) processing for retrieving dispersed error encoded data in accordance with the present invention;

FIG. 26 is a schematic block diagram of an example of a dispersed error decoding for the example of FIG. 25 in accordance with the present invention;

FIG. 27 is a schematic block diagram of an example of a distributed storage and task processing network (DSTN) module storing a plurality of data and a plurality of task codes in accordance with the present invention;

FIG. 28 is a schematic block diagram of an example of the distributed computing system performing tasks on stored data in accordance with the present invention;

FIG. 29 is a schematic block diagram of an embodiment of a task distribution module facilitating the example of FIG. 28 in accordance with the present invention;

FIG. 30 is a diagram of a specific example of the distributed computing system performing tasks on stored data in accordance with the present invention;

FIG. 31 is a schematic block diagram of an example of a distributed storage and task processing network (DSTN) module storing data and task codes for the example of FIG. 30 in accordance with the present invention;

FIG. 32 is a diagram of an example of DST allocation information for the example of FIG. 30 in accordance with the present invention;

FIGS. 33-38 are schematic block diagrams of the DSTN module performing the example of FIG. 30 in accordance with the present invention;

FIG. 39 is a diagram of an example of combining result information into final results for the example of FIG. 30 in accordance with the present invention;

FIG. 40A is a schematic block diagram of an embodiment of a decentralized agreement module in accordance with the present invention;

FIG. 40B is a flowchart illustrating an example of selecting the resource in accordance with the present invention;

FIG. 40C is a schematic block diagram of an embodiment of a dispersed storage network (DSN) in accordance with the present invention;

FIG. 40D is a flowchart illustrating an example of accessing a dispersed storage network (DSN) memory in accordance with the present invention;

FIG. 41A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) in accordance with the present invention;

FIG. 41B is a flowchart illustrating an example of authorizing a slice access request in accordance with the present invention;

FIG. 42A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) in accordance with the present invention;

FIG. 42B is a flowchart illustrating an example of determining status of the slice migration in accordance with the present invention;

FIG. 43A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) in accordance with the present invention;

FIG. 43B is a flowchart illustrating an example of modifying a data access approach for stored data in accordance with the present invention;

FIGS. 44A-E are schematic block diagrams of another embodiment of a dispersed storage network (DSN) in accordance with the present invention;

FIG. 44F is a flowchart illustrating an example of selecting storage units in accordance with the present invention;

FIG. 45A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) in accordance with the present invention;

FIG. 45B is a flowchart illustrating an example of pacing migration of encoded data slices in accordance with the present invention;

FIG. 46A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) in accordance with the present invention;

FIG. 46B is a flowchart illustrating an example of handling a memory device error condition in accordance with the present invention;

FIG. 47A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) in accordance with the present invention;

FIG. 47B is a flowchart illustrating an example of recovering data stored in a dispersed storage network (DSN) in accordance with the present invention;

FIGS. 48A-B are a schematic block diagram of another embodiment of a dispersed storage network (DSN) in accordance with the present invention;

FIG. 48C is a flowchart illustrating an example of maintaining encoded data slice storage with regards to power utilization in accordance with the present invention;

FIG. 49A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) in accordance with the present invention; and

FIG. 49B is a flowchart illustrating an example of coordinating task execution amongst a set of storage units in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of an embodiment of a distributed computing system 10 that includes a user device 12 and/or a user device 14, a distributed storage and/or task (DST) processing unit 16, a distributed storage and/or task network (DSTN) managing unit 18, a DST integrity processing unit 20, and a distributed storage and/or task network (DSTN) module 22. The components of the distributed computing system 10 are coupled via a network 24, which may include one or more wireless and/or wire lined communication systems; one or more private intranet systems and/or public internet systems; and/or one or more local area networks (LAN) and/or wide area networks (WAN).

The DSTN module 22 includes a plurality of distributed storage and/or task (DST) execution units 36 that may be located at geographically different sites (e.g., one in Chicago, one in Milwaukee, etc.). Each of the DST execution units is operable to store dispersed error encoded data and/or to execute, in a distributed manner, one or more tasks on data. The tasks may be a simple function (e.g., a mathematical function, a logic function, an identify function, a find function, a search engine function, a replace function, etc.), a complex function (e.g., compression, human and/or computer language translation, text-to-voice conversion, voice-to-text conversion, etc.), multiple simple and/or complex functions, one or more algorithms, one or more applications, etc.

Each of the user devices 12-14, the DST processing unit 16, the DSTN managing unit 18, and the DST integrity processing unit 20 include a computing core 26 and may be a portable computing device and/or a fixed computing device. A portable computing device may be a social networking device, a gaming device, a cell phone, a smart phone, a personal digital assistant, a digital music player, a digital video player, a laptop computer, a handheld computer, a tablet, a video game controller, and/or any other portable device that includes a computing core. A fixed computing device may be a personal computer (PC), a computer server, a cable set-top box, a satellite receiver, a television set, a printer, a fax machine, home entertainment equipment, a video game console, and/or any type of home or office computing equipment. User device 12 and DST processing unit 16 are configured to include a DST client module 34.

With respect to interfaces, each interface 30, 32, and 33 includes software and/or hardware to support one or more communication links via the network 24 indirectly and/or directly. For example, interface 30 supports a communication link (e.g., wired, wireless, direct, via a LAN, via the network 24, etc.) between user device 14 and the DST processing unit 16. As another example, interface 32 supports communication links (e.g., a wired connection, a wireless connection, a LAN connection, and/or any other type of connection to/from the network 24) between user device 12 and the DSTN module 22 and between the DST processing unit 16 and the DSTN module 22. As yet another example, interface 33 supports a communication link for each of the DSTN managing unit 18 and DST integrity processing unit 20 to the network 24.

The distributed computing system 10 is operable to support dispersed storage (DS) error encoded data storage and retrieval, to support distributed task processing on received data, and/or to support distributed task processing on stored data. In general and with respect to DS error encoded data storage and retrieval, the distributed computing system 10 supports three primary operations: storage management, data storage and retrieval (an example of which will be discussed with reference to FIGS. 20-26), and data storage integrity verification. In accordance with these three primary functions, data can be encoded, distributedly stored in physically different locations, and subsequently retrieved in a reliable and secure manner. Such a system is tolerant of a significant number of failures (e.g., up to a failure level, which may be greater than or equal to a pillar width minus a decode threshold minus one) that may result from individual storage device failures and/or network equipment failures without loss of data and without the need for a redundant or backup copy. Further, the system allows the data to be stored for an indefinite period of time without data loss and does so in a secure manner (e.g., the system is very resistant to attempts at hacking the data).

The second primary function (i.e., distributed data storage and retrieval) begins and ends with a user device 12-14. For instance, if a second type of user device 14 has data 40 to store in the DSTN module 22, it sends the data 40 to the DST processing unit 16 via its interface 30. The interface 30 functions to mimic a conventional operating system (OS) file system interface (e.g., network file system (NFS), flash file system (FFS), disk file system (DFS), file transfer protocol (FTP), web-based distributed authoring and versioning (WebDAV), etc.) and/or a block memory interface (e.g., small computer system interface (SCSI), internet small computer system interface (iSCSI), etc.). In addition, the interface 30 may attach a user identification code (ID) to the data 40.

To support storage management, the DSTN managing unit 18 performs DS management services. One such DS management service includes the DSTN managing unit 18 establishing distributed data storage parameters (e.g., vault creation, distributed storage parameters, security parameters, billing information, user profile information, etc.) for a user device 12-14 individually or as part of a group of user devices. For example, the DSTN managing unit 18 coordinates creation of a vault (e.g., a virtual memory block) within memory of the DSTN module 22 for a user device, a group of devices, or for public access and establishes per vault dispersed storage (DS) error encoding parameters for a vault. The DSTN managing unit 18 may facilitate storage of DS error encoding parameters for each vault of a plurality of vaults by updating registry information for the distributed computing system 10. The facilitating includes storing updated registry information in one or more of the DSTN module 22, the user device 12, the DST processing unit 16, and the DST integrity processing unit 20.

The DS error encoding parameters (e.g., or dispersed storage error coding parameters) include data segmenting information (e.g., how many segments data (e.g., a file, a group of files, a data block, etc.) is divided into), segment security information (e.g., per segment encryption, compression, integrity checksum, etc.), error coding information (e.g., pillar width, decode threshold, read threshold, write threshold, etc.), slicing information (e.g., the number of encoded data slices that will be created for each data segment); and slice security information (e.g., per encoded data slice encryption, compression, integrity checksum, etc.).

The DSTN managing unit 18 creates and stores user profile information (e.g., an access control list (ACL)) in local memory and/or within memory of the DSTN module 22. The user profile information includes authentication information, permissions, and/or the security parameters. The security parameters may include encryption/decryption scheme, one or more encryption keys, key generation scheme, and/or data encoding/decoding scheme.

The DSTN managing unit 18 creates billing information for a particular user, a user group, a vault access, public vault access, etc. For instance, the DSTN managing unit 18 tracks the number of times a user accesses a private vault and/or public vaults, which can be used to generate a per-access billing information. In another instance, the DSTN managing unit 18 tracks the amount of data stored and/or retrieved by a user device and/or a user group, which can be used to generate a per-data-amount billing information.

Another DS management service includes the DSTN managing unit 18 performing network operations, network administration, and/or network maintenance. Network operations includes authenticating user data allocation requests (e.g., read and/or write requests), managing creation of vaults, establishing authentication credentials for user devices, adding/deleting components (e.g., user devices, DST execution units, and/or DST processing units) from the distributed computing system 10, and/or establishing authentication credentials for DST execution units 36. Network administration includes monitoring devices and/or units for failures, maintaining vault information, determining device and/or unit activation status, determining device and/or unit loading, and/or determining any other system level operation that affects the performance level of the system 10. Network maintenance includes facilitating replacing, upgrading, repairing, and/or expanding a device and/or unit of the system 10.

To support data storage integrity verification within the distributed computing system 10, the DST integrity processing unit 20 performs rebuilding of ‘bad’ or missing encoded data slices. At a high level, the DST integrity processing unit 20 performs rebuilding by periodically attempting to retrieve/list encoded data slices, and/or slice names of the encoded data slices, from the DSTN module 22. For retrieved encoded slices, they are checked for errors due to data corruption, outdated version, etc. If a slice includes an error, it is flagged as a ‘bad’ slice. For encoded data slices that were not received and/or not listed, they are flagged as missing slices. Bad and/or missing slices are subsequently rebuilt using other retrieved encoded data slices that are deemed to be good slices to produce rebuilt slices. The rebuilt slices are stored in memory of the DSTN module 22. Note that the DST integrity processing unit 20 may be a separate unit as shown, it may be included in the DSTN module 22, it may be included in the DST processing unit 16, and/or distributed among the DST execution units 36.

To support distributed task processing on received data, the distributed computing system 10 has two primary operations: DST (distributed storage and/or task processing) management and DST execution on received data (an example of which will be discussed with reference to FIGS. 3-19). With respect to the storage portion of the DST management, the DSTN managing unit 18 functions as previously described. With respect to the tasking processing of the DST management, the DSTN managing unit 18 performs distributed task processing (DTP) management services. One such DTP management service includes the DSTN managing unit 18 establishing DTP parameters (e.g., user-vault affiliation information, billing information, user-task information, etc.) for a user device 12-14 individually or as part of a group of user devices.

Another DTP management service includes the DSTN managing unit 18 performing DTP network operations, network administration (which is essentially the same as described above), and/or network maintenance (which is essentially the same as described above). Network operations include, but are not limited to, authenticating user task processing requests (e.g., valid request, valid user, etc.), authenticating results and/or partial results, establishing DTP authentication credentials for user devices, adding/deleting components (e.g., user devices, DST execution units, and/or DST processing units) from the distributed computing system, and/or establishing DTP authentication credentials for DST execution units.

To support distributed task processing on stored data, the distributed computing system 10 has two primary operations: DST (distributed storage and/or task) management and DST execution on stored data. With respect to the DST execution on stored data, if the second type of user device 14 has a task request 38 for execution by the DSTN module 22, it sends the task request 38 to the DST processing unit 16 via its interface 30. An example of DST execution on stored data will be discussed in greater detail with reference to FIGS. 27-39. With respect to the DST management, it is substantially similar to the DST management to support distributed task processing on received data.

FIG. 2 is a schematic block diagram of an embodiment of a computing core 26 that includes a processing module 50, a memory controller 52, main memory 54, a video graphics processing unit 55, an input/output (TO) controller 56, a peripheral component interconnect (PCI) interface 58, an IO interface module 60, at least one IO device interface module 62, a read only memory (ROM) basic input output system (BIOS) 64, and one or more memory interface modules. The one or more memory interface module(s) includes one or more of a universal serial bus (USB) interface module 66, a host bus adapter (HBA) interface module 68, a network interface module 70, a flash interface module 72, a hard drive interface module 74, and a DSTN interface module 76.

The DSTN interface module 76 functions to mimic a conventional operating system (OS) file system interface (e.g., network file system (NFS), flash file system (FFS), disk file system (DFS), file transfer protocol (FTP), web-based distributed authoring and versioning (WebDAV), etc.) and/or a block memory interface (e.g., small computer system interface (SCSI), internet small computer system interface (iSCSI), etc.). The DSTN interface module 76 and/or the network interface module 70 may function as the interface 30 of the user device 14 of FIG. 1. Further note that the IO device interface module 62 and/or the memory interface modules may be collectively or individually referred to as 10 ports.

FIG. 3 is a diagram of an example of the distributed computing system performing a distributed storage and task processing operation. The distributed computing system includes a DST (distributed storage and/or task) client module 34 (which may be in user device 14 and/or in DST processing unit 16 of FIG. 1), a network 24, a plurality of DST execution units 1-n that includes two or more DST execution units 36 of FIG. 1 (which form at least a portion of DSTN module 22 of FIG. 1), a DST managing module (not shown), and a DST integrity verification module (not shown). The DST client module 34 includes an outbound DST processing section 80 and an inbound DST processing section 82. Each of the DST execution units 1-n includes a controller 86, a processing module 84, memory 88, a DT (distributed task) execution module 90, and a DST client module 34.

In an example of operation, the DST client module 34 receives data 92 and one or more tasks 94 to be performed upon the data 92. The data 92 may be of any size and of any content, where, due to the size (e.g., greater than a few Terabytes), the content (e.g., secure data, etc.), and/or task(s) (e.g., MIPS intensive), distributed processing of the task(s) on the data is desired. For example, the data 92 may be one or more digital books, a copy of a company's emails, a large-scale Internet search, a video security file, one or more entertainment video files (e.g., television programs, movies, etc.), data files, and/or any other large amount of data (e.g., greater than a few Terabytes).

Within the DST client module 34, the outbound DST processing section 80 receives the data 92 and the task(s) 94. The outbound DST processing section 80 processes the data 92 to produce slice groupings 96. As an example of such processing, the outbound DST processing section 80 partitions the data 92 into a plurality of data partitions. For each data partition, the outbound DST processing section 80 dispersed storage (DS) error encodes the data partition to produce encoded data slices and groups the encoded data slices into a slice grouping 96. In addition, the outbound DST processing section 80 partitions the task 94 into partial tasks 98, where the number of partial tasks 98 may correspond to the number of slice groupings 96.

The outbound DST processing section 80 then sends, via the network 24, the slice groupings 96 and the partial tasks 98 to the DST execution units 1-n of the DSTN module 22 of FIG. 1. For example, the outbound DST processing section 80 sends slice group 1 and partial task 1 to DST execution unit 1. As another example, the outbound DST processing section 80 sends slice group #n and partial task #n to DST execution unit #n.

Each DST execution unit performs its partial task 98 upon its slice group 96 to produce partial results 102. For example, DST execution unit #1 performs partial task #1 on slice group #1 to produce a partial result #1, for results. As a more specific example, slice group #1 corresponds to a data partition of a series of digital books and the partial task #1 corresponds to searching for specific phrases, recording where the phrase is found, and establishing a phrase count. In this more specific example, the partial result #1 includes information as to where the phrase was found and includes the phrase count.

Upon completion of generating their respective partial results 102, the DST execution units send, via the network 24, their partial results 102 to the inbound DST processing section 82 of the DST client module 34. The inbound DST processing section 82 processes the received partial results 102 to produce a result 104. Continuing with the specific example of the preceding paragraph, the inbound DST processing section 82 combines the phrase count from each of the DST execution units 36 to produce a total phrase count. In addition, the inbound DST processing section 82 combines the ‘where the phrase was found’ information from each of the DST execution units 36 within their respective data partitions to produce ‘where the phrase was found’ information for the series of digital books.

In another example of operation, the DST client module 34 requests retrieval of stored data within the memory of the DST execution units 36 (e.g., memory of the DSTN module). In this example, the task 94 is retrieve data stored in the memory of the DSTN module. Accordingly, the outbound DST processing section 80 converts the task 94 into a plurality of partial tasks 98 and sends the partial tasks 98 to the respective DST execution units 1-n.

In response to the partial task 98 of retrieving stored data, a DST execution unit 36 identifies the corresponding encoded data slices 100 and retrieves them. For example, DST execution unit #1 receives partial task #1 and retrieves, in response thereto, retrieved slices #1. The DST execution units 36 send their respective retrieved slices 100 to the inbound DST processing section 82 via the network 24.

The inbound DST processing section 82 converts the retrieved slices 100 into data 92. For example, the inbound DST processing section 82 de-groups the retrieved slices 100 to produce encoded slices per data partition. The inbound DST processing section 82 then DS error decodes the encoded slices per data partition to produce data partitions. The inbound DST processing section 82 de-partitions the data partitions to recapture the data 92.

FIG. 4 is a schematic block diagram of an embodiment of an outbound distributed storage and/or task (DST) processing section 80 of a DST client module 34 FIG. 1 coupled to a DSTN module 22 of a FIG. 1 (e.g., a plurality of n DST execution units 36) via a network 24. The outbound DST processing section 80 includes a data partitioning module 110, a dispersed storage (DS) error encoding module 112, a grouping selector module 114, a control module 116, and a distributed task control module 118.

In an example of operation, the data partitioning module 110 partitions data 92 into a plurality of data partitions 120. The number of partitions and the size of the partitions may be selected by the control module 116 via control 160 based on the data 92 (e.g., its size, its content, etc.), a corresponding task 94 to be performed (e.g., simple, complex, single step, multiple steps, etc.), DS encoding parameters (e.g., pillar width, decode threshold, write threshold, segment security parameters, slice security parameters, etc.), capabilities of the DST execution units 36 (e.g., processing resources, availability of processing recourses, etc.), and/or as may be inputted by a user, system administrator, or other operator (human or automated). For example, the data partitioning module 110 partitions the data 92 (e.g., 100 Terabytes) into 100,000 data segments, each being 1 Gigabyte in size. Alternatively, the data partitioning module 110 partitions the data 92 into a plurality of data segments, where some of data segments are of a different size, are of the same size, or a combination thereof.

The DS error encoding module 112 receives the data partitions 120 in a serial manner, a parallel manner, and/or a combination thereof. For each data partition 120, the DS error encoding module 112 DS error encodes the data partition 120 in accordance with control information 160 from the control module 116 to produce encoded data slices 122. The DS error encoding includes segmenting the data partition into data segments, segment security processing (e.g., encryption, compression, watermarking, integrity check (e.g., CRC), etc.), error encoding, slicing, and/or per slice security processing (e.g., encryption, compression, watermarking, integrity check (e.g., CRC), etc.). The control information 160 indicates which steps of the DS error encoding are active for a given data partition and, for active steps, indicates the parameters for the step. For example, the control information 160 indicates that the error encoding is active and includes error encoding parameters (e.g., pillar width, decode threshold, write threshold, read threshold, type of error encoding, etc.).

The grouping selector module 114 groups the encoded slices 122 of a data partition into a set of slice groupings 96. The number of slice groupings corresponds to the number of DST execution units 36 identified for a particular task 94. For example, if five DST execution units 36 are identified for the particular task 94, the grouping selector module groups the encoded slices 122 of a data partition into five slice groupings 96. The grouping selector module 114 outputs the slice groupings 96 to the corresponding DST execution units 36 via the network 24.

The distributed task control module 118 receives the task 94 and converts the task 94 into a set of partial tasks 98. For example, the distributed task control module 118 receives a task to find where in the data (e.g., a series of books) a phrase occurs and a total count of the phrase usage in the data. In this example, the distributed task control module 118 replicates the task 94 for each DST execution unit 36 to produce the partial tasks 98. In another example, the distributed task control module 118 receives a task to find where in the data a first phrase occurs, where in the data a second phrase occurs, and a total count for each phrase usage in the data. In this example, the distributed task control module 118 generates a first set of partial tasks 98 for finding and counting the first phrase and a second set of partial tasks for finding and counting the second phrase. The distributed task control module 118 sends respective first and/or second partial tasks 98 to each DST execution unit 36.

FIG. 5 is a logic diagram of an example of a method for outbound distributed storage and task (DST) processing that begins at step 126 where a DST client module receives data and one or more corresponding tasks. The method continues at step 128 where the DST client module determines a number of DST units to support the task for one or more data partitions. For example, the DST client module may determine the number of DST units to support the task based on the size of the data, the requested task, the content of the data, a predetermined number (e.g., user indicated, system administrator determined, etc.), available DST units, capability of the DST units, and/or any other factor regarding distributed task processing of the data. The DST client module may select the same DST units for each data partition, may select different DST units for the data partitions, or a combination thereof.

The method continues at step 130 where the DST client module determines processing parameters of the data based on the number of DST units selected for distributed task processing. The processing parameters include data partitioning information, DS encoding parameters, and/or slice grouping information. The data partitioning information includes a number of data partitions, size of each data partition, and/or organization of the data partitions (e.g., number of data blocks in a partition, the size of the data blocks, and arrangement of the data blocks). The DS encoding parameters include segmenting information, segment security information, error encoding information (e.g., dispersed storage error encoding function parameters including one or more of pillar width, decode threshold, write threshold, read threshold, generator matrix), slicing information, and/or per slice security information. The slice grouping information includes information regarding how to arrange the encoded data slices into groups for the selected DST units. As a specific example, if the DST client module determines that five DST units are needed to support the task, then it determines that the error encoding parameters include a pillar width of five and a decode threshold of three.

The method continues at step 132 where the DST client module determines task partitioning information (e.g., how to partition the tasks) based on the selected DST units and data processing parameters. The data processing parameters include the processing parameters and DST unit capability information. The DST unit capability information includes the number of DT (distributed task) execution units, execution capabilities of each DT execution unit (e.g., MIPS capabilities, processing resources (e.g., quantity and capability of microprocessors, CPUs, digital signal processors, co-processor, microcontrollers, arithmetic logic circuitry, and/or any other analog and/or digital processing circuitry), availability of the processing resources, memory information (e.g., type, size, availability, etc.)), and/or any information germane to executing one or more tasks.

The method continues at step 134 where the DST client module processes the data in accordance with the processing parameters to produce slice groupings. The method continues at step 136 where the DST client module partitions the task based on the task partitioning information to produce a set of partial tasks. The method continues at step 138 where the DST client module sends the slice groupings and the corresponding partial tasks to respective DST units.

FIG. 6 is a schematic block diagram of an embodiment of the dispersed storage (DS) error encoding module 112 of an outbound distributed storage and task (DST) processing section. The DS error encoding module 112 includes a segment processing module 142, a segment security processing module 144, an error encoding module 146, a slicing module 148, and a per slice security processing module 150. Each of these modules is coupled to a control module 116 to receive control information 160 therefrom.

In an example of operation, the segment processing module 142 receives a data partition 120 from a data partitioning module and receives segmenting information as the control information 160 from the control module 116. The segmenting information indicates how the segment processing module 142 is to segment the data partition 120. For example, the segmenting information indicates how many rows to segment the data based on a decode threshold of an error encoding scheme, indicates how many columns to segment the data into based on a number and size of data blocks within the data partition 120, and indicates how many columns to include in a data segment 152. The segment processing module 142 segments the data 120 into data segments 152 in accordance with the segmenting information.

The segment security processing module 144, when enabled by the control module 116, secures the data segments 152 based on segment security information received as control information 160 from the control module 116. The segment security information includes data compression, encryption, watermarking, integrity check (e.g., cyclic redundancy check (CRC), etc.), and/or any other type of digital security. For example, when the segment security processing module 144 is enabled, it may compress a data segment 152, encrypt the compressed data segment, and generate a CRC value for the encrypted data segment to produce a secure data segment 154. When the segment security processing module 144 is not enabled, it passes the data segments 152 to the error encoding module 146 or is bypassed such that the data segments 152 are provided to the error encoding module 146.

The error encoding module 146 encodes the secure data segments 154 in accordance with error correction encoding parameters received as control information 160 from the control module 116. The error correction encoding parameters (e.g., also referred to as dispersed storage error coding parameters) include identifying an error correction encoding scheme (e.g., forward error correction algorithm, a Reed-Solomon based algorithm, an online coding algorithm, an information dispersal algorithm, etc.), a pillar width, a decode threshold, a read threshold, a write threshold, etc. For example, the error correction encoding parameters identify a specific error correction encoding scheme, specifies a pillar width of five, and specifies a decode threshold of three. From these parameters, the error encoding module 146 encodes a data segment 154 to produce an encoded data segment 156.

The slicing module 148 slices the encoded data segment 156 in accordance with the pillar width of the error correction encoding parameters received as control information 160. For example, if the pillar width is five, the slicing module 148 slices an encoded data segment 156 into a set of five encoded data slices. As such, for a plurality of encoded data segments 156 for a given data partition, the slicing module outputs a plurality of sets of encoded data slices 158.

The per slice security processing module 150, when enabled by the control module 116, secures each encoded data slice 158 based on slice security information received as control information 160 from the control module 116. The slice security information includes data compression, encryption, watermarking, integrity check (e.g., CRC, etc.), and/or any other type of digital security. For example, when the per slice security processing module 150 is enabled, it compresses an encoded data slice 158, encrypts the compressed encoded data slice, and generates a CRC value for the encrypted encoded data slice to produce a secure encoded data slice 122. When the per slice security processing module 150 is not enabled, it passes the encoded data slices 158 or is bypassed such that the encoded data slices 158 are the output of the DS error encoding module 112. Note that the control module 116 may be omitted and each module stores its own parameters.

FIG. 7 is a diagram of an example of a segment processing of a dispersed storage (DS) error encoding module. In this example, a segment processing module 142 receives a data partition 120 that includes 45 data blocks (e.g., d1-d45), receives segmenting information (i.e., control information 160) from a control module, and segments the data partition 120 in accordance with the control information 160 to produce data segments 152. Each data block may be of the same size as other data blocks or of a different size. In addition, the size of each data block may be a few bytes to megabytes of data. As previously mentioned, the segmenting information indicates how many rows to segment the data partition into, indicates how many columns to segment the data partition into, and indicates how many columns to include in a data segment.

In this example, the decode threshold of the error encoding scheme is three; as such the number of rows to divide the data partition into is three. The number of columns for each row is set to 15, which is based on the number and size of data blocks. The data blocks of the data partition are arranged in rows and columns in a sequential order (i.e., the first row includes the first 15 data blocks; the second row includes the second 15 data blocks; and the third row includes the last 15 data blocks).

With the data blocks arranged into the desired sequential order, they are divided into data segments based on the segmenting information. In this example, the data partition is divided into 8 data segments; the first 7 include 2 columns of three rows and the last includes 1 column of three rows. Note that the first row of the 8 data segments is in sequential order of the first 15 data blocks; the second row of the 8 data segments in sequential order of the second 15 data blocks; and the third row of the 8 data segments in sequential order of the last 15 data blocks. Note that the number of data blocks, the grouping of the data blocks into segments, and size of the data blocks may vary to accommodate the desired distributed task processing function.

FIG. 8 is a diagram of an example of error encoding and slicing processing of the dispersed error encoding processing the data segments of FIG. 7. In this example, data segment 1 includes 3 rows with each row being treated as one word for encoding. As such, data segment 1 includes three words for encoding: word 1 including data blocks d1 and d2, word 2 including data blocks d16 and d17, and word 3 including data blocks d31 and d32. Each of data segments 2-7 includes three words where each word includes two data blocks. Data segment 8 includes three words where each word includes a single data block (e.g., d15, d30, and d45).

In operation, an error encoding module 146 and a slicing module 148 convert each data segment into a set of encoded data slices in accordance with error correction encoding parameters as control information 160. More specifically, when the error correction encoding parameters indicate a unity matrix Reed-Solomon based encoding algorithm, 5 pillars, and decode threshold of 3, the first three encoded data slices of the set of encoded data slices for a data segment are substantially similar to the corresponding word of the data segment. For instance, when the unity matrix Reed-Solomon based encoding algorithm is applied to data segment 1, the content of the first encoded data slice (DS1_d1&2) of the first set of encoded data slices (e.g., corresponding to data segment 1) is substantially similar to content of the first word (e.g., d1 & d2); the content of the second encoded data slice (DS1_d16&17) of the first set of encoded data slices is substantially similar to content of the second word (e.g., d16 & d17); and the content of the third encoded data slice (DS1_d31&32) of the first set of encoded data slices is substantially similar to content of the third word (e.g., d31 & d32).

The content of the fourth and fifth encoded data slices (e.g., ES1_1 and ES1_2) of the first set of encoded data slices include error correction data based on the first-third words of the first data segment. With such an encoding and slicing scheme, retrieving any three of the five encoded data slices allows the data segment to be accurately reconstructed.

The encoding and slicing of data segments 2-7 yield sets of encoded data slices similar to the set of encoded data slices of data segment 1. For instance, the content of the first encoded data slice (DS2_d3&4) of the second set of encoded data slices (e.g., corresponding to data segment 2) is substantially similar to content of the first word (e.g., d3 & d4); the content of the second encoded data slice (DS2_d18&19) of the second set of encoded data slices is substantially similar to content of the second word (e.g., d18 & d19); and the content of the third encoded data slice (DS2_d33&34) of the second set of encoded data slices is substantially similar to content of the third word (e.g., d33 & d34). The content of the fourth and fifth encoded data slices (e.g., ES1_1 and ES1_2) of the second set of encoded data slices includes error correction data based on the first-third words of the second data segment.

FIG. 9 is a diagram of an example of grouping selection processing of an outbound distributed storage and task (DST) processing in accordance with grouping selection information as control information 160 from a control module. Encoded slices for data partition 122 are grouped in accordance with the control information 160 to produce slice groupings 96. In this example, a grouping selector module 114 organizes the encoded data slices into five slice groupings (e.g., one for each DST execution unit of a distributed storage and task network (DSTN) module). As a specific example, the grouping selector module 114 creates a first slice grouping for a DST execution unit #1, which includes first encoded slices of each of the sets of encoded slices. As such, the first DST execution unit receives encoded data slices corresponding to data blocks 1-15 (e.g., encoded data slices of contiguous data).

The grouping selector module 114 also creates a second slice grouping for a DST execution unit #2, which includes second encoded slices of each of the sets of encoded slices. As such, the second DST execution unit receives encoded data slices corresponding to data blocks 16-30. The grouping selector module 114 further creates a third slice grouping for DST execution unit #3, which includes third encoded slices of each of the sets of encoded slices. As such, the third DST execution unit receives encoded data slices corresponding to data blocks 31-45.

The grouping selector module 114 creates a fourth slice grouping for DST execution unit #4, which includes fourth encoded slices of each of the sets of encoded slices. As such, the fourth DST execution unit receives encoded data slices corresponding to first error encoding information (e.g., encoded data slices of error coding (EC) data). The grouping selector module 114 further creates a fifth slice grouping for DST execution unit #5, which includes fifth encoded slices of each of the sets of encoded slices. As such, the fifth DST execution unit receives encoded data slices corresponding to second error encoding information.

FIG. 10 is a diagram of an example of converting data 92 into slice groups that expands on the preceding figures. As shown, the data 92 is partitioned in accordance with a partitioning function 164 into a plurality of data partitions (1-x, where x is an integer greater than 4). Each data partition (or chunkset of data) is encoded and grouped into slice groupings as previously discussed by an encoding and grouping function 166. For a given data partition, the slice groupings are sent to distributed storage and task (DST) execution units. From data partition to data partition, the ordering of the slice groupings to the DST execution units may vary.

For example, the slice groupings of data partition #1 is sent to the DST execution units such that the first DST execution receives first encoded data slices of each of the sets of encoded data slices, which corresponds to a first continuous data chunk of the first data partition (e.g., refer to FIG. 9), a second DST execution receives second encoded data slices of each of the sets of encoded data slices, which corresponds to a second continuous data chunk of the first data partition, etc.

For the second data partition, the slice groupings may be sent to the DST execution units in a different order than it was done for the first data partition. For instance, the first slice grouping of the second data partition (e.g., slice group 2_1) is sent to the second DST execution unit; the second slice grouping of the second data partition (e.g., slice group 2_2) is sent to the third DST execution unit; the third slice grouping of the second data partition (e.g., slice group 2_3) is sent to the fourth DST execution unit; the fourth slice grouping of the second data partition (e.g., slice group 2_4, which includes first error coding information) is sent to the fifth DST execution unit; and the fifth slice grouping of the second data partition (e.g., slice group 2_5, which includes second error coding information) is sent to the first DST execution unit.

The pattern of sending the slice groupings to the set of DST execution units may vary in a predicted pattern, a random pattern, and/or a combination thereof from data partition to data partition. In addition, from data partition to data partition, the set of DST execution units may change. For example, for the first data partition, DST execution units 1-5 may be used; for the second data partition, DST execution units 6-10 may be used; for the third data partition, DST execution units 3-7 may be used; etc. As is also shown, the task is divided into partial tasks that are sent to the DST execution units in conjunction with the slice groupings of the data partitions.

FIG. 11 is a schematic block diagram of an embodiment of a DST (distributed storage and/or task) execution unit that includes an interface 169, a controller 86, memory 88, one or more DT (distributed task) execution modules 90, and a DST client module 34. The memory 88 is of sufficient size to store a significant number of encoded data slices (e.g., thousands of slices to hundreds-of-millions of slices) and may include one or more hard drives and/or one or more solid-state memory devices (e.g., flash memory, DRAM, etc.).

In an example of storing a slice group, the DST execution module receives a slice grouping 96 (e.g., slice group #1) via interface 169. The slice grouping 96 includes, per partition, encoded data slices of contiguous data or encoded data slices of error coding (EC) data. For slice group #1, the DST execution module receives encoded data slices of contiguous data for partitions #1 and #x (and potentially others between 3 and x) and receives encoded data slices of EC data for partitions #2 and #3 (and potentially others between 3 and x). Examples of encoded data slices of contiguous data and encoded data slices of error coding (EC) data are discussed with reference to FIG. 9. The memory 88 stores the encoded data slices of slice groupings 96 in accordance with memory control information 174 it receives from the controller 86.

The controller 86 (e.g., a processing module, a CPU, etc.) generates the memory control information 174 based on a partial task(s) 98 and distributed computing information (e.g., user information (e.g., user ID, distributed computing permissions, data access permission, etc.), vault information (e.g., virtual memory assigned to user, user group, temporary storage for task processing, etc.), task validation information, etc.). For example, the controller 86 interprets the partial task(s) 98 in light of the distributed computing information to determine whether a requestor is authorized to perform the task 98, is authorized to access the data, and/or is authorized to perform the task on this particular data. When the requestor is authorized, the controller 86 determines, based on the task 98 and/or another input, whether the encoded data slices of the slice grouping 96 are to be temporarily stored or permanently stored. Based on the foregoing, the controller 86 generates the memory control information 174 to write the encoded data slices of the slice grouping 96 into the memory 88 and to indicate whether the slice grouping 96 is permanently stored or temporarily stored.

With the slice grouping 96 stored in the memory 88, the controller 86 facilitates execution of the partial task(s) 98. In an example, the controller 86 interprets the partial task 98 in light of the capabilities of the DT execution module(s) 90. The capabilities include one or more of MIPS capabilities, processing resources (e.g., quantity and capability of microprocessors, CPUs, digital signal processors, co-processor, microcontrollers, arithmetic logic circuitry, and/or any other analog and/or digital processing circuitry), availability of the processing resources, etc. If the controller 86 determines that the DT execution module(s) 90 have sufficient capabilities, it generates task control information 176.

The task control information 176 may be a generic instruction (e.g., perform the task on the stored slice grouping) or a series of operational codes. In the former instance, the DT execution module 90 includes a co-processor function specifically configured (fixed or programmed) to perform the desired task 98. In the latter instance, the DT execution module 90 includes a general processor topology where the controller stores an algorithm corresponding to the particular task 98. In this instance, the controller 86 provides the operational codes (e.g., assembly language, source code of a programming language, object code, etc.) of the algorithm to the DT execution module 90 for execution.

Depending on the nature of the task 98, the DT execution module 90 may generate intermediate partial results 102 that are stored in the memory 88 or in a cache memory (not shown) within the DT execution module 90. In either case, when the DT execution module 90 completes execution of the partial task 98, it outputs one or more partial results 102. The partial results 102 may also be stored in memory 88.

If, when the controller 86 is interpreting whether capabilities of the DT execution module(s) 90 can support the partial task 98, the controller 86 determines that the DT execution module(s) 90 cannot adequately support the task 98 (e.g., does not have the right resources, does not have sufficient available resources, available resources would be too slow, etc.), it then determines whether the partial task 98 should be fully offloaded or partially offloaded.

If the controller 86 determines that the partial task 98 should be fully offloaded, it generates DST control information 178 and provides it to the DST client module 34. The DST control information 178 includes the partial task 98, memory storage information regarding the slice grouping 96, and distribution instructions. The distribution instructions instruct the DST client module 34 to divide the partial task 98 into sub-partial tasks 172, to divide the slice grouping 96 into sub-slice groupings 170, and identify other DST execution units. The DST client module 34 functions in a similar manner as the DST client module 34 of FIGS. 3-10 to produce the sub-partial tasks 172 and the sub-slice groupings 170 in accordance with the distribution instructions.

The DST client module 34 receives DST feedback 168 (e.g., sub-partial results), via the interface 169, from the DST execution units to which the task was offloaded. The DST client module 34 provides the sub-partial results to the DST execution unit, which processes the sub-partial results to produce the partial result(s) 102.

If the controller 86 determines that the partial task 98 should be partially offloaded, it determines what portion of the task 98 and/or slice grouping 96 should be processed locally and what should be offloaded. For the portion that is being locally processed, the controller 86 generates task control information 176 as previously discussed. For the portion that is being offloaded, the controller 86 generates DST control information 178 as previously discussed.

When the DST client module 34 receives DST feedback 168 (e.g., sub-partial results) from the DST executions units to which a portion of the task was offloaded, it provides the sub-partial results to the DT execution module 90. The DT execution module 90 processes the sub-partial results with the sub-partial results it created to produce the partial result(s) 102.

The memory 88 may be further utilized to retrieve one or more of stored slices 100, stored results 104, partial results 102 when the DT execution module 90 stores partial results 102 and/or results 104 in the memory 88. For example, when the partial task 98 includes a retrieval request, the controller 86 outputs the memory control 174 to the memory 88 to facilitate retrieval of slices 100 and/or results 104.

FIG. 12 is a schematic block diagram of an example of operation of a distributed storage and task (DST) execution unit storing encoded data slices and executing a task thereon. To store the encoded data slices of a partition 1 of slice grouping 1, a controller 86 generates write commands as memory control information 174 such that the encoded slices are stored in desired locations (e.g., permanent or temporary) within memory 88.

Once the encoded slices are stored, the controller 86 provides task control information 176 to a distributed task (DT) execution module 90. As a first step of executing the task in accordance with the task control information 176, the DT execution module 90 retrieves the encoded slices from memory 88. The DT execution module 90 then reconstructs contiguous data blocks of a data partition. As shown for this example, reconstructed contiguous data blocks of data partition 1 include data blocks 1-15 (e.g., d1-d15).

With the contiguous data blocks reconstructed, the DT execution module 90 performs the task on the reconstructed contiguous data blocks. For example, the task may be to search the reconstructed contiguous data blocks for a particular word or phrase, identify where in the reconstructed contiguous data blocks the particular word or phrase occurred, and/or count the occurrences of the particular word or phrase on the reconstructed contiguous data blocks. The DST execution unit continues in a similar manner for the encoded data slices of other partitions in slice grouping 1. Note that with using the unity matrix error encoding scheme previously discussed, if the encoded data slices of contiguous data are uncorrupted, the decoding of them is a relatively straightforward process of extracting the data.

If, however, an encoded data slice of contiguous data is corrupted (or missing), it can be rebuilt by accessing other DST execution units that are storing the other encoded data slices of the set of encoded data slices of the corrupted encoded data slice. In this instance, the DST execution unit having the corrupted encoded data slices retrieves at least three encoded data slices (of contiguous data and of error coding data) in the set from the other DST execution units (recall for this example, the pillar width is 5 and the decode threshold is 3). The DST execution unit decodes the retrieved data slices using the DS error encoding parameters to recapture the corresponding data segment. The DST execution unit then re-encodes the data segment using the DS error encoding parameters to rebuild the corrupted encoded data slice. Once the encoded data slice is rebuilt, the DST execution unit functions as previously described.

FIG. 13 is a schematic block diagram of an embodiment of an inbound distributed storage and/or task (DST) processing section 82 of a DST client module coupled to DST execution units of a distributed storage and task network (DSTN) module via a network 24. The inbound DST processing section 82 includes a de-grouping module 180, a DS (dispersed storage) error decoding module 182, a data de-partitioning module 184, a control module 186, and a distributed task control module 188. Note that the control module 186 and/or the distributed task control module 188 may be separate modules from corresponding ones of outbound DST processing section or may be the same modules.

In an example of operation, the DST execution units have completed execution of corresponding partial tasks on the corresponding slice groupings to produce partial results 102. The inbound DST processing section 82 receives the partial results 102 via the distributed task control module 188. The inbound DST processing section 82 then processes the partial results 102 to produce a final result, or results 104. For example, if the task was to find a specific word or phrase within data, the partial results 102 indicate where in each of the prescribed portions of the data the corresponding DST execution units found the specific word or phrase. The distributed task control module 188 combines the individual partial results 102 for the corresponding portions of the data into a final result 104 for the data as a whole.

In another example of operation, the inbound DST processing section 82 is retrieving stored data from the DST execution units (i.e., the DSTN module). In this example, the DST execution units output encoded data slices 100 corresponding to the data retrieval requests. The de-grouping module 180 receives retrieved slices 100 and de-groups them to produce encoded data slices per data partition 122. The DS error decoding module 182 decodes, in accordance with DS error encoding parameters, the encoded data slices per data partition 122 to produce data partitions 120.

The data de-partitioning module 184 combines the data partitions 120 into the data 92. The control module 186 controls the conversion of retrieved slices 100 into the data 92 using control signals 190 to each of the modules. For instance, the control module 186 provides de-grouping information to the de-grouping module 180, provides the DS error encoding parameters to the DS error decoding module 182, and provides de-partitioning information to the data de-partitioning module 184.

FIG. 14 is a logic diagram of an example of a method that is executable by distributed storage and task (DST) client module regarding inbound DST processing. The method begins at step 194 where the DST client module receives partial results. The method continues at step 196 where the DST client module retrieves the task corresponding to the partial results. For example, the partial results include header information that identifies the requesting entity, which correlates to the requested task.

The method continues at step 198 where the DST client module determines result processing information based on the task. For example, if the task were to identify a particular word or phrase within the data, the result processing information would indicate to aggregate the partial results for the corresponding portions of the data to produce the final result. As another example, if the task were to count the occurrences of a particular word or phrase within the data, results of processing the information would indicate to add the partial results to produce the final results. The method continues at step 200 where the DST client module processes the partial results in accordance with the result processing information to produce the final result or results.

FIG. 15 is a diagram of an example of de-grouping selection processing of an inbound distributed storage and task (DST) processing section of a DST client module. In general, this is an inverse process of the grouping module of the outbound DST processing section of FIG. 9. Accordingly, for each data partition (e.g., partition #1), the de-grouping module retrieves the corresponding slice grouping from the DST execution units (EU) (e.g., DST 1-5).

As shown, DST execution unit #1 provides a first slice grouping, which includes the first encoded slices of each of the sets of encoded slices (e.g., encoded data slices of contiguous data of data blocks 1-15); DST execution unit #2 provides a second slice grouping, which includes the second encoded slices of each of the sets of encoded slices (e.g., encoded data slices of contiguous data of data blocks 16-30); DST execution unit #3 provides a third slice grouping, which includes the third encoded slices of each of the sets of encoded slices (e.g., encoded data slices of contiguous data of data blocks 31-45); DST execution unit #4 provides a fourth slice grouping, which includes the fourth encoded slices of each of the sets of encoded slices (e.g., first encoded data slices of error coding (EC) data); and DST execution unit #5 provides a fifth slice grouping, which includes the fifth encoded slices of each of the sets of encoded slices (e.g., first encoded data slices of error coding (EC) data).

The de-grouping module de-groups the slice groupings (e.g., received slices 100) using a de-grouping selector 180 controlled by a control signal 190 as shown in the example to produce a plurality of sets of encoded data slices (e.g., retrieved slices for a partition into sets of slices 122). Each set corresponding to a data segment of the data partition.

FIG. 16 is a schematic block diagram of an embodiment of a dispersed storage (DS) error decoding module 182 of an inbound distributed storage and task (DST) processing section. The DS error decoding module 182 includes an inverse per slice security processing module 202, a de-slicing module 204, an error decoding module 206, an inverse segment security module 208, a de-segmenting processing module 210, and a control module 186.

In an example of operation, the inverse per slice security processing module 202, when enabled by the control module 186, unsecures each encoded data slice 122 based on slice de-security information received as control information 190 (e.g., the compliment of the slice security information discussed with reference to FIG. 6) received from the control module 186. The slice security information includes data decompression, decryption, de-watermarking, integrity check (e.g., CRC verification, etc.), and/or any other type of digital security. For example, when the inverse per slice security processing module 202 is enabled, it verifies integrity information (e.g., a CRC value) of each encoded data slice 122, it decrypts each verified encoded data slice, and decompresses each decrypted encoded data slice to produce slice encoded data 158. When the inverse per slice security processing module 202 is not enabled, it passes the encoded data slices 122 as the sliced encoded data 158 or is bypassed such that the retrieved encoded data slices 122 are provided as the sliced encoded data 158.

The de-slicing module 204 de-slices the sliced encoded data 158 into encoded data segments 156 in accordance with a pillar width of the error correction encoding parameters received as control information 190 from the control module 186. For example, if the pillar width is five, the de-slicing module 204 de-slices a set of five encoded data slices into an encoded data segment 156. The error decoding module 206 decodes the encoded data segments 156 in accordance with error correction decoding parameters received as control information 190 from the control module 186 to produce secure data segments 154. The error correction decoding parameters include identifying an error correction encoding scheme (e.g., forward error correction algorithm, a Reed-Solomon based algorithm, an information dispersal algorithm, etc.), a pillar width, a decode threshold, a read threshold, a write threshold, etc. For example, the error correction decoding parameters identify a specific error correction encoding scheme, specify a pillar width of five, and specify a decode threshold of three.

The inverse segment security processing module 208, when enabled by the control module 186, unsecures the secured data segments 154 based on segment security information received as control information 190 from the control module 186. The segment security information includes data decompression, decryption, de-watermarking, integrity check (e.g., CRC, etc.) verification, and/or any other type of digital security. For example, when the inverse segment security processing module 208 is enabled, it verifies integrity information (e.g., a CRC value) of each secure data segment 154, it decrypts each verified secured data segment, and decompresses each decrypted secure data segment to produce a data segment 152. When the inverse segment security processing module 208 is not enabled, it passes the decoded data segment 154 as the data segment 152 or is bypassed.

The de-segment processing module 210 receives the data segments 152 and receives de-segmenting information as control information 190 from the control module 186. The de-segmenting information indicates how the de-segment processing module 210 is to de-segment the data segments 152 into a data partition 120. For example, the de-segmenting information indicates how the rows and columns of data segments are to be rearranged to yield the data partition 120.

FIG. 17 is a diagram of an example of de-slicing and error decoding processing of a dispersed error decoding module. A de-slicing module 204 receives at least a decode threshold number of encoded data slices 158 for each data segment in accordance with control information 190 and provides encoded data 156. In this example, a decode threshold is three. As such, each set of encoded data slices 158 is shown to have three encoded data slices per data segment. The de-slicing module 204 may receive three encoded data slices per data segment because an associated distributed storage and task (DST) client module requested retrieving only three encoded data slices per segment or selected three of the retrieved encoded data slices per data segment. As shown, which is based on the unity matrix encoding previously discussed with reference to FIG. 8, an encoded data slice may be a data-based encoded data slice (e.g., DS1_d1&d2) or an error code based encoded data slice (e.g., ES3_1).

An error decoding module 206 decodes the encoded data 156 of each data segment in accordance with the error correction decoding parameters of control information 190 to produce secured segments 154. In this example, data segment 1 includes 3 rows with each row being treated as one word for encoding. As such, data segment 1 includes three words: word 1 including data blocks d1 and d2, word 2 including data blocks d16 and d17, and word 3 including data blocks d31 and d32. Each of data segments 2-7 includes three words where each word includes two data blocks. Data segment 8 includes three words where each word includes a single data block (e.g., d15, d30, and d45).

FIG. 18 is a diagram of an example of de-segment processing of an inbound distributed storage and task (DST) processing. In this example, a de-segment processing module 210 receives data segments 152 (e.g., 1-8) and rearranges the data blocks of the data segments into rows and columns in accordance with de-segmenting information of control information 190 to produce a data partition 120. Note that the number of rows is based on the decode threshold (e.g., 3 in this specific example) and the number of columns is based on the number and size of the data blocks.

The de-segmenting module 210 converts the rows and columns of data blocks into the data partition 120. Note that each data block may be of the same size as other data blocks or of a different size. In addition, the size of each data block may be a few bytes to megabytes of data.

FIG. 19 is a diagram of an example of converting slice groups into data 92 within an inbound distributed storage and task (DST) processing section. As shown, the data 92 is reconstructed from a plurality of data partitions (1-x, where x is an integer greater than 4). Each data partition (or chunk set of data) is decoded and re-grouped using a de-grouping and decoding function 212 and a de-partition function 214 from slice groupings as previously discussed. For a given data partition, the slice groupings (e.g., at least a decode threshold per data segment of encoded data slices) are received from DST execution units. From data partition to data partition, the ordering of the slice groupings received from the DST execution units may vary as discussed with reference to FIG. 10.

FIG. 20 is a diagram of an example of a distributed storage and/or retrieval within the distributed computing system. The distributed computing system includes a plurality of distributed storage and/or task (DST) processing client modules 34 (one shown) coupled to a distributed storage and/or task processing network (DSTN) module, or multiple DSTN modules, via a network 24. The DST client module 34 includes an outbound DST processing section 80 and an inbound DST processing section 82. The DSTN module includes a plurality of DST execution units. Each DST execution unit includes a controller 86, memory 88, one or more distributed task (DT) execution modules 90, and a DST client module 34.

In an example of data storage, the DST client module 34 has data 92 that it desires to store in the DSTN module. The data 92 may be a file (e.g., video, audio, text, graphics, etc.), a data object, a data block, an update to a file, an update to a data block, etc. In this instance, the outbound DST processing module 80 converts the data 92 into encoded data slices 216 as will be further described with reference to FIGS. 21-23. The outbound DST processing module 80 sends, via the network 24, to the DST execution units for storage as further described with reference to FIG. 24.

In an example of data retrieval, the DST client module 34 issues a retrieve request to the DST execution units for the desired data 92. The retrieve request may address each DST executions units storing encoded data slices of the desired data, address a decode threshold number of DST execution units, address a read threshold number of DST execution units, or address some other number of DST execution units. In response to the request, each addressed DST execution unit retrieves its encoded data slices 100 of the desired data and sends them to the inbound DST processing section 82, via the network 24.

When, for each data segment, the inbound DST processing section 82 receives at least a decode threshold number of encoded data slices 100, it converts the encoded data slices 100 into a data segment. The inbound DST processing section 82 aggregates the data segments to produce the retrieved data 92.

FIG. 21 is a schematic block diagram of an embodiment of an outbound distributed storage and/or task (DST) processing section 80 of a DST client module coupled to a distributed storage and task network (DSTN) module (e.g., a plurality of DST execution units) via a network 24. The outbound DST processing section 80 includes a data partitioning module 110, a dispersed storage (DS) error encoding module 112, a grouping selector module 114, a control module 116, and a distributed task control module 118.

In an example of operation, the data partitioning module 110 is by-passed such that data 92 is provided directly to the DS error encoding module 112. The control module 116 coordinates the by-passing of the data partitioning module 110 by outputting a bypass 220 message to the data partitioning module 110.

The DS error encoding module 112 receives the data 92 in a serial manner, a parallel manner, and/or a combination thereof. The DS error encoding module 112 DS error encodes the data in accordance with control information 160 from the control module 116 to produce encoded data slices 218. The DS error encoding includes segmenting the data 92 into data segments, segment security processing (e.g., encryption, compression, watermarking, integrity check (e.g., CRC, etc.)), error encoding, slicing, and/or per slice security processing (e.g., encryption, compression, watermarking, integrity check (e.g., CRC, etc.)). The control information 160 indicates which steps of the DS error encoding are active for the data 92 and, for active steps, indicates the parameters for the step. For example, the control information 160 indicates that the error encoding is active and includes error encoding parameters (e.g., pillar width, decode threshold, write threshold, read threshold, type of error encoding, etc.).

The grouping selector module 114 groups the encoded slices 218 of the data segments into pillars of slices 216. The number of pillars corresponds to the pillar width of the DS error encoding parameters. In this example, the distributed task control module 118 facilitates the storage request.

FIG. 22 is a schematic block diagram of an example of a dispersed storage (DS) error encoding module 112 for the example of FIG. 21. The DS error encoding module 112 includes a segment processing module 142, a segment security processing module 144, an error encoding module 146, a slicing module 148, and a per slice security processing module 150. Each of these modules is coupled to a control module 116 to receive control information 160 therefrom.

In an example of operation, the segment processing module 142 receives data 92 and receives segmenting information as control information 160 from the control module 116. The segmenting information indicates how the segment processing module is to segment the data. For example, the segmenting information indicates the size of each data segment. The segment processing module 142 segments the data 92 into data segments 152 in accordance with the segmenting information.

The segment security processing module 144, when enabled by the control module 116, secures the data segments 152 based on segment security information received as control information 160 from the control module 116. The segment security information includes data compression, encryption, watermarking, integrity check (e.g., CRC, etc.), and/or any other type of digital security. For example, when the segment security processing module 144 is enabled, it compresses a data segment 152, encrypts the compressed data segment, and generates a CRC value for the encrypted data segment to produce a secure data segment. When the segment security processing module 144 is not enabled, it passes the data segments 152 to the error encoding module 146 or is bypassed such that the data segments 152 are provided to the error encoding module 146.

The error encoding module 146 encodes the secure data segments in accordance with error correction encoding parameters received as control information 160 from the control module 116. The error correction encoding parameters include identifying an error correction encoding scheme (e.g., forward error correction algorithm, a Reed-Solomon based algorithm, an information dispersal algorithm, etc.), a pillar width, a decode threshold, a read threshold, a write threshold, etc. For example, the error correction encoding parameters identify a specific error correction encoding scheme, specifies a pillar width of five, and specifies a decode threshold of three. From these parameters, the error encoding module 146 encodes a data segment to produce an encoded data segment.

The slicing module 148 slices the encoded data segment in accordance with a pillar width of the error correction encoding parameters. For example, if the pillar width is five, the slicing module slices an encoded data segment into a set of five encoded data slices. As such, for a plurality of data segments, the slicing module 148 outputs a plurality of sets of encoded data slices as shown within encoding and slicing function 222 as described.

The per slice security processing module 150, when enabled by the control module 116, secures each encoded data slice based on slice security information received as control information 160 from the control module 116. The slice security information includes data compression, encryption, watermarking, integrity check (e.g., CRC, etc.), and/or any other type of digital security. For example, when the per slice security processing module 150 is enabled, it may compress an encoded data slice, encrypt the compressed encoded data slice, and generate a CRC value for the encrypted encoded data slice to produce a secure encoded data slice tweaking. When the per slice security processing module 150 is not enabled, it passes the encoded data slices or is bypassed such that the encoded data slices 218 are the output of the DS error encoding module 112.

FIG. 23 is a diagram of an example of converting data 92 into pillar slice groups utilizing encoding, slicing and pillar grouping function 224 for storage in memory of a distributed storage and task network (DSTN) module. As previously discussed the data 92 is encoded and sliced into a plurality of sets of encoded data slices; one set per data segment. The grouping selector module organizes the sets of encoded data slices into pillars of data slices. In this example, the DS error encoding parameters include a pillar width of 5 and a decode threshold of 3. As such, for each data segment, 5 encoded data slices are created.

The grouping selector module takes the first encoded data slice of each of the sets and forms a first pillar, which may be sent to the first DST execution unit. Similarly, the grouping selector module creates the second pillar from the second slices of the sets; the third pillar from the third slices of the sets; the fourth pillar from the fourth slices of the sets; and the fifth pillar from the fifth slices of the set.

FIG. 24 is a schematic block diagram of an embodiment of a distributed storage and/or task (DST) execution unit that includes an interface 169, a controller 86, memory 88, one or more distributed task (DT) execution modules 90, and a DST client module 34. A computing core 26 may be utilized to implement the one or more DT execution modules 90 and the DST client module 34. The memory 88 is of sufficient size to store a significant number of encoded data slices (e.g., thousands of slices to hundreds-of-millions of slices) and may include one or more hard drives and/or one or more solid-state memory devices (e.g., flash memory, DRAM, etc.).

In an example of storing a pillar of slices 216, the DST execution unit receives, via interface 169, a pillar of slices 216 (e.g., pillar #1 slices). The memory 88 stores the encoded data slices 216 of the pillar of slices in accordance with memory control information 174 it receives from the controller 86. The controller 86 (e.g., a processing module, a CPU, etc.) generates the memory control information 174 based on distributed storage information (e.g., user information (e.g., user ID, distributed storage permissions, data access permission, etc.), vault information (e.g., virtual memory assigned to user, user group, etc.), etc.). Similarly, when retrieving slices, the DST execution unit receives, via interface 169, a slice retrieval request. The memory 88 retrieves the slice in accordance with memory control information 174 it receives from the controller 86. The memory 88 outputs the slice 100, via the interface 169, to a requesting entity.

FIG. 25 is a schematic block diagram of an example of operation of an inbound distributed storage and/or task (DST) processing section 82 for retrieving dispersed error encoded data 92. The inbound DST processing section 82 includes a de-grouping module 180, a dispersed storage (DS) error decoding module 182, a data de-partitioning module 184, a control module 186, and a distributed task control module 188. Note that the control module 186 and/or the distributed task control module 188 may be separate modules from corresponding ones of an outbound DST processing section or may be the same modules.

In an example of operation, the inbound DST processing section 82 is retrieving stored data 92 from the DST execution units (i.e., the DSTN module). In this example, the DST execution units output encoded data slices corresponding to data retrieval requests from the distributed task control module 188. The de-grouping module 180 receives pillars of slices 100 and de-groups them in accordance with control information 190 from the control module 186 to produce sets of encoded data slices 218. The DS error decoding module 182 decodes, in accordance with the DS error encoding parameters received as control information 190 from the control module 186, each set of encoded data slices 218 to produce data segments, which are aggregated into retrieved data 92. The data de-partitioning module 184 is by-passed in this operational mode via a bypass signal 226 of control information 190 from the control module 186.

FIG. 26 is a schematic block diagram of an embodiment of a dispersed storage (DS) error decoding module 182 of an inbound distributed storage and task (DST) processing section. The DS error decoding module 182 includes an inverse per slice security processing module 202, a de-slicing module 204, an error decoding module 206, an inverse segment security module 208, and a de-segmenting processing module 210. The dispersed error decoding module 182 is operable to de-slice and decode encoded slices per data segment 218 utilizing a de-slicing and decoding function 228 to produce a plurality of data segments that are de-segmented utilizing a de-segment function 230 to recover data 92.

In an example of operation, the inverse per slice security processing module 202, when enabled by the control module 186 via control information 190, unsecures each encoded data slice 218 based on slice de-security information (e.g., the compliment of the slice security information discussed with reference to FIG. 6) received as control information 190 from the control module 186. The slice de-security information includes data decompression, decryption, de-watermarking, integrity check (e.g., CRC verification, etc.), and/or any other type of digital security. For example, when the inverse per slice security processing module 202 is enabled, it verifies integrity information (e.g., a CRC value) of each encoded data slice 218, it decrypts each verified encoded data slice, and decompresses each decrypted encoded data slice to produce slice encoded data. When the inverse per slice security processing module 202 is not enabled, it passes the encoded data slices 218 as the sliced encoded data or is bypassed such that the retrieved encoded data slices 218 are provided as the sliced encoded data.

The de-slicing module 204 de-slices the sliced encoded data into encoded data segments in accordance with a pillar width of the error correction encoding parameters received as control information 190 from a control module 186. For example, if the pillar width is five, the de-slicing module de-slices a set of five encoded data slices into an encoded data segment. Alternatively, the encoded data segment may include just three encoded data slices (e.g., when the decode threshold is 3).

The error decoding module 206 decodes the encoded data segments in accordance with error correction decoding parameters received as control information 190 from the control module 186 to produce secure data segments. The error correction decoding parameters include identifying an error correction encoding scheme (e.g., forward error correction algorithm, a Reed-Solomon based algorithm, an information dispersal algorithm, etc.), a pillar width, a decode threshold, a read threshold, a write threshold, etc. For example, the error correction decoding parameters identify a specific error correction encoding scheme, specify a pillar width of five, and specify a decode threshold of three.

The inverse segment security processing module 208, when enabled by the control module 186, unsecures the secured data segments based on segment security information received as control information 190 from the control module 186. The segment security information includes data decompression, decryption, de-watermarking, integrity check (e.g., CRC, etc.) verification, and/or any other type of digital security. For example, when the inverse segment security processing module is enabled, it verifies integrity information (e.g., a CRC value) of each secure data segment, it decrypts each verified secured data segment, and decompresses each decrypted secure data segment to produce a data segment 152. When the inverse segment security processing module 208 is not enabled, it passes the decoded data segment 152 as the data segment or is bypassed. The de-segmenting processing module 210 aggregates the data segments 152 into the data 92 in accordance with control information 190 from the control module 186.

FIG. 27 is a schematic block diagram of an example of a distributed storage and task processing network (DSTN) module that includes a plurality of distributed storage and task (DST) execution units (#1 through #n, where, for example, n is an integer greater than or equal to three). Each of the DST execution units includes a DST client module 34, a controller 86, one or more DT (distributed task) execution modules 90, and memory 88.

In this example, the DSTN module stores, in the memory of the DST execution units, a plurality of DS (dispersed storage) encoded data (e.g., 1 through n, where n is an integer greater than or equal to two) and stores a plurality of DS encoded task codes (e.g., 1 through k, where k is an integer greater than or equal to two). The DS encoded data may be encoded in accordance with one or more examples described with reference to FIGS. 3-19 (e.g., organized in slice groupings) or encoded in accordance with one or more examples described with reference to FIGS. 20-26 (e.g., organized in pillar groups). The data that is encoded into the DS encoded data may be of any size and/or of any content. For example, the data may be one or more digital books, a copy of a company's emails, a large-scale Internet search, a video security file, one or more entertainment video files (e.g., television programs, movies, etc.), data files, and/or any other large amount of data (e.g., greater than a few Terabytes).

The tasks that are encoded into the DS encoded task code may be a simple function (e.g., a mathematical function, a logic function, an identify function, a find function, a search engine function, a replace function, etc.), a complex function (e.g., compression, human and/or computer language translation, text-to-voice conversion, voice-to-text conversion, etc.), multiple simple and/or complex functions, one or more algorithms, one or more applications, etc. The tasks may be encoded into the DS encoded task code in accordance with one or more examples described with reference to FIGS. 3-19 (e.g., organized in slice groupings) or encoded in accordance with one or more examples described with reference to FIGS. 20-26 (e.g., organized in pillar groups).

In an example of operation, a DST client module of a user device or of a DST processing unit issues a DST request to the DSTN module. The DST request may include a request to retrieve stored data, or a portion thereof, may include a request to store data that is included with the DST request, may include a request to perform one or more tasks on stored data, may include a request to perform one or more tasks on data included with the DST request, etc. In the cases where the DST request includes a request to store data or to retrieve data, the client module and/or the DSTN module processes the request as previously discussed with reference to one or more of FIGS. 3-19 (e.g., slice groupings) and/or 20-26 (e.g., pillar groupings). In the case where the DST request includes a request to perform one or more tasks on data included with the DST request, the DST client module and/or the DSTN module process the DST request as previously discussed with reference to one or more of FIGS. 3-19.

In the case where the DST request includes a request to perform one or more tasks on stored data, the DST client module and/or the DSTN module processes the DST request as will be described with reference to one or more of FIGS. 28-39. In general, the DST client module identifies data and one or more tasks for the DSTN module to execute upon the identified data. The DST request may be for a one-time execution of the task or for an on-going execution of the task. As an example of the latter, as a company generates daily emails, the DST request may be to daily search new emails for inappropriate content and, if found, record the content, the email sender(s), the email recipient(s), email routing information, notify human resources of the identified email, etc.

FIG. 28 is a schematic block diagram of an example of a distributed computing system performing tasks on stored data. In this example, two distributed storage and task (DST) client modules 1-2 are shown: the first may be associated with a user device and the second may be associated with a DST processing unit or a high priority user device (e.g., high priority clearance user, system administrator, etc.). Each DST client module includes a list of stored data 234 and a list of tasks codes 236. The list of stored data 234 includes one or more entries of data identifying information, where each entry identifies data stored in the DSTN module 22. The data identifying information (e.g., data ID) includes one or more of a data file name, a data file directory listing, DSTN addressing information of the data, a data object identifier, etc. The list of tasks 236 includes one or more entries of task code identifying information, when each entry identifies task codes stored in the DSTN module 22. The task code identifying information (e.g., task ID) includes one or more of a task file name, a task file directory listing, DSTN addressing information of the task, another type of identifier to identify the task, etc.

As shown, the list of data 234 and the list of tasks 236 are each smaller in number of entries for the first DST client module than the corresponding lists of the second DST client module. This may occur because the user device associated with the first DST client module has fewer privileges in the distributed computing system than the device associated with the second DST client module. Alternatively, this may occur because the user device associated with the first DST client module serves fewer users than the device associated with the second DST client module and is restricted by the distributed computing system accordingly. As yet another alternative, this may occur through no restraints by the distributed computing system, it just occurred because the operator of the user device associated with the first DST client module has selected fewer data and/or fewer tasks than the operator of the device associated with the second DST client module.

In an example of operation, the first DST client module selects one or more data entries 238 and one or more tasks 240 from its respective lists (e.g., selected data ID and selected task ID). The first DST client module sends its selections to a task distribution module 232. The task distribution module 232 may be within a stand-alone device of the distributed computing system, may be within the user device that contains the first DST client module, or may be within the DSTN module 22.

Regardless of the task distribution module's location, it generates DST allocation information 242 from the selected task ID 240 and the selected data ID 238. The DST allocation information 242 includes data partitioning information, task execution information, and/or intermediate result information. The task distribution module 232 sends the DST allocation information 242 to the DSTN module 22. Note that one or more examples of the DST allocation information will be discussed with reference to one or more of FIGS. 29-39.

The DSTN module 22 interprets the DST allocation information 242 to identify the stored DS encoded data (e.g., DS error encoded data 2) and to identify the stored DS error encoded task code (e.g., DS error encoded task code 1). In addition, the DSTN module 22 interprets the DST allocation information 242 to determine how the data is to be partitioned and how the task is to be partitioned. The DSTN module 22 also determines whether the selected DS error encoded data 238 needs to be converted from pillar grouping to slice grouping. If so, the DSTN module 22 converts the selected DS error encoded data into slice groupings and stores the slice grouping DS error encoded data by overwriting the pillar grouping DS error encoded data or by storing it in a different location in the memory of the DSTN module 22 (i.e., does not overwrite the pillar grouping DS encoded data).

The DSTN module 22 partitions the data and the task as indicated in the DST allocation information 242 and sends the portions to selected DST execution units of the DSTN module 22. Each of the selected DST execution units performs its partial task(s) on its slice groupings to produce partial results. The DSTN module 22 collects the partial results from the selected DST execution units and provides them, as result information 244, to the task distribution module. The result information 244 may be the collected partial results, one or more final results as produced by the DSTN module 22 from processing the partial results in accordance with the DST allocation information 242, or one or more intermediate results as produced by the DSTN module 22 from processing the partial results in accordance with the DST allocation information 242.

The task distribution module 232 receives the result information 244 and provides one or more final results 104 therefrom to the first DST client module. The final result(s) 104 may be result information 244 or a result(s) of the task distribution module's processing of the result information 244.

In concurrence with processing the selected task of the first DST client module, the distributed computing system may process the selected task(s) of the second DST client module on the selected data(s) of the second DST client module. Alternatively, the distributed computing system may process the second DST client module's request subsequent to, or preceding, that of the first DST client module. Regardless of the ordering and/or parallel processing of the DST client module requests, the second DST client module provides its selected data 238 and selected task 240 to a task distribution module 232. If the task distribution module 232 is a separate device of the distributed computing system or within the DSTN module, the task distribution modules 232 coupled to the first and second DST client modules may be the same module. The task distribution module 232 processes the request of the second DST client module in a similar manner as it processed the request of the first DST client module.

FIG. 29 is a schematic block diagram of an embodiment of a task distribution module 232 facilitating the example of FIG. 28. The task distribution module 232 includes a plurality of tables it uses to generate distributed storage and task (DST) allocation information 242 for selected data and selected tasks received from a DST client module. The tables include data storage information 248, task storage information 250, distributed task (DT) execution module information 252, and task

sub-task mapping information 246.

The data storage information table 248 includes a data identification (ID) field 260, a data size field 262, an addressing information field 264, distributed storage (DS) information 266, and may further include other information regarding the data, how it is stored, and/or how it can be processed. For example, DS encoded data #1 has a data ID of 1, a data size of AA (e.g., a byte size of a few Terabytes or more), addressing information of Addr_1_AA, and DS parameters of 3/5; SEG_1; and SLC_1. In this example, the addressing information may be a virtual address corresponding to the virtual address of the first storage word (e.g., one or more bytes) of the data and information on how to calculate the other addresses, may be a range of virtual addresses for the storage words of the data, physical addresses of the first storage word or the storage words of the data, may be a list of slice names of the encoded data slices of the data, etc. The DS parameters may include identity of an error encoding scheme, decode threshold/pillar width (e.g., 3/5 for the first data entry), segment security information (e.g., SEG_1), per slice security information (e.g., SLC_1), and/or any other information regarding how the data was encoded into data slices.

The task storage information table 250 includes a task identification (ID) field 268, a task size field 270, an addressing information field 272, distributed storage (DS) information 274, and may further include other information regarding the task, how it is stored, and/or how it can be used to process data. For example, DS encoded task #2 has a task ID of 2, a task size of XY, addressing information of Addr_2_XY, and DS parameters of 3/5; SEG_2; and SLC_2. In this example, the addressing information may be a virtual address corresponding to the virtual address of the first storage word (e.g., one or more bytes) of the task and information on how to calculate the other addresses, may be a range of virtual addresses for the storage words of the task, physical addresses of the first storage word or the storage words of the task, may be a list of slices names of the encoded slices of the task code, etc. The DS parameters may include identity of an error encoding scheme, decode threshold/pillar width (e.g., 3/5 for the first data entry), segment security information (e.g., SEG_2), per slice security information (e.g., SLC_2), and/or any other information regarding how the task was encoded into encoded task slices. Note that the segment and/or the per-slice security information include a type of encryption (if enabled), a type of compression (if enabled), watermarking information (if enabled), and/or an integrity check scheme (if enabled).

The task

sub-task mapping information table 246 includes a task field 256 and a sub-task field 258. The task field 256 identifies a task stored in the memory of a distributed storage and task network (DSTN) module and the corresponding sub-task fields 258 indicates whether the task includes sub-tasks and, if so, how many and if any of the sub-tasks are ordered. In this example, the task

sub-task mapping information table 246 includes an entry for each task stored in memory of the DSTN module (e.g., task 1 through task k). In particular, this example indicates that task 1 includes 7 sub-tasks; task 2 does not include sub-tasks, and task k includes r number of sub-tasks (where r is an integer greater than or equal to two).

The DT execution module table 252 includes a DST execution unit ID field 276, a DT execution module ID field 278, and a DT execution module capabilities field 280. The DST execution unit ID field 276 includes the identity of DST units in the DSTN module. The DT execution module ID field 278 includes the identity of each DT execution unit in each DST unit. For example, DST unit 1 includes three DT executions modules (e.g., 1_1, 1_2, and 1_3). The DT execution capabilities field 280 includes identity of the capabilities of the corresponding DT execution unit. For example, DT execution module 1_1 includes capabilities X, where X includes one or more of MIPS capabilities, processing resources (e.g., quantity and capability of microprocessors, CPUs, digital signal processors, co-processor, microcontrollers, arithmetic logic circuitry, and/or any other analog and/or digital processing circuitry), availability of the processing resources, memory information (e.g., type, size, availability, etc.), and/or any information germane to executing one or more tasks.

From these tables, the task distribution module 232 generates the DST allocation information 242 to indicate where the data is stored, how to partition the data, where the task is stored, how to partition the task, which DT execution units should perform which partial task on which data partitions, where and how intermediate results are to be stored, etc. If multiple tasks are being performed on the same data or different data, the task distribution module factors such information into its generation of the DST allocation information.

FIG. 30 is a diagram of a specific example of a distributed computing system performing tasks on stored data as a task flow 318. In this example, selected data 92 is data 2 and selected tasks are tasks 1, 2, and 3. Task 1 corresponds to analyzing translation of data from one language to another (e.g., human language or computer language); task 2 corresponds to finding specific words and/or phrases in the data; and task 3 corresponds to finding specific translated words and/or phrases in translated data.

In this example, task 1 includes 7 sub-tasks: task 1_1—identify non-words (non-ordered); task 1_2—identify unique words (non-ordered); task 1_3—translate (non-ordered); task 1_4—translate back (ordered after task 1_3); task 1_5—compare to ID errors (ordered after task 1-4); task 1_6—determine non-word translation errors (ordered after task 1_5 and 1_1); and task 1_7—determine correct translations (ordered after 1_5 and 1_2). The sub-task further indicates whether they are an ordered task (i.e., are dependent on the outcome of another task) or non-order (i.e., are independent of the outcome of another task). Task 2 does not include sub-tasks and task 3 includes two sub-tasks: task 3_1 translate; and task 3_2 find specific word or phrase in translated data.

In general, the three tasks collectively are selected to analyze data for translation accuracies, translation errors, translation anomalies, occurrence of specific words or phrases in the data, and occurrence of specific words or phrases on the translated data. Graphically, the data 92 is translated 306 into translated data 282; is analyzed for specific words and/or phrases 300 to produce a list of specific words and/or phrases 286; is analyzed for non-words 302 (e.g., not in a reference dictionary) to produce a list of non-words 290; and is analyzed for unique words 316 included in the data 92 (i.e., how many different words are included in the data) to produce a list of unique words 298. Each of these tasks is independent of each other and can therefore be processed in parallel if desired.

The translated data 282 is analyzed (e.g., sub-task 3_2) for specific translated words and/or phrases 304 to produce a list of specific translated words and/or phrases 288. The translated data 282 is translated back 308 (e.g., sub-task 1_4) into the language of the original data to produce re-translated data 284. These two tasks are dependent on the translate task (e.g., task 1_3) and thus must be ordered after the translation task, which may be in a pipelined ordering or a serial ordering. The re-translated data 284 is then compared 310 with the original data 92 to find words and/or phrases that did not translate (one way and/or the other) properly to produce a list of incorrectly translated words 294. As such, the comparing task (e.g., sub-task 1_5) 310 is ordered after the translation 306 and re-translation tasks 308 (e.g., sub-tasks 1_3 and 1_4).

The list of words incorrectly translated 294 is compared 312 to the list of non-words 290 to identify words that were not properly translated because the words are non-words to produce a list of errors due to non-words 292. In addition, the list of words incorrectly translated 294 is compared 314 to the list of unique words 298 to identify unique words that were properly translated to produce a list of correctly translated words 296. The comparison may also identify unique words that were not properly translated to produce a list of unique words that were not properly translated. Note that each list of words (e.g., specific words and/or phrases, non-words, unique words, translated words and/or phrases, etc.,) may include the word and/or phrase, how many times it is used, where in the data it is used, and/or any other information requested regarding a word and/or phrase.

FIG. 31 is a schematic block diagram of an example of a distributed storage and task processing network (DSTN) module storing data and task codes for the example of FIG. 30. As shown, DS encoded data 2 is stored as encoded data slices across the memory (e.g., stored in memories 88) of DST execution units 1-5; the DS encoded task code 1 (of task 1) and DS encoded task 3 are stored as encoded task slices across the memory of DST execution units 1-5; and DS encoded task code 2 (of task 2) is stored as encoded task slices across the memory of DST execution units 3-7. As indicated in the data storage information table and the task storage information table of FIG. 29, the respective data/task has DS parameters of 3/5 for their decode threshold/pillar width; hence spanning the memory of five DST execution units.

FIG. 32 is a diagram of an example of distributed storage and task (DST) allocation information 242 for the example of FIG. 30. The DST allocation information 242 includes data partitioning information 320, task execution information 322, and intermediate result information 324. The data partitioning information 320 includes the data identifier (ID), the number of partitions to split the data into, address information for each data partition, and whether the DS encoded data has to be transformed from pillar grouping to slice grouping. The task execution information 322 includes tabular information having a task identification field 326, a task ordering field 328, a data partition field ID 330, and a set of DT execution modules 332 to use for the distributed task processing per data partition. The intermediate result information 324 includes tabular information having a name ID field 334, an ID of the DST execution unit assigned to process the corresponding intermediate result 336, a scratch pad storage field 338, and an intermediate result storage field 340.

Continuing with the example of FIG. 30, where tasks 1-3 are to be distributedly performed on data 2, the data partitioning information includes the ID of data 2. In addition, the task distribution module determines whether the DS encoded data 2 is in the proper format for distributed computing (e.g., was stored as slice groupings). If not, the task distribution module indicates that the DS encoded data 2 format needs to be changed from the pillar grouping format to the slice grouping format, which will be done by the DSTN module. In addition, the task distribution module determines the number of partitions to divide the data into (e.g., 2_1 through 2_z) and addressing information for each partition.

The task distribution module generates an entry in the task execution information section for each sub-task to be performed. For example, task 1_1 (e.g., identify non-words on the data) has no task ordering (i.e., is independent of the results of other sub-tasks), is to be performed on data partitions 2_1 through 2_z by DT execution modules 1_1, 2_1, 3_1, 4_1, and 5_1. For instance, DT execution modules 1_1, 2_1, 3_1, 4_1, and 5_1 search for non-words in data partitions 2_1 through 2_z to produce task 1_1 intermediate results (R1-1, which is a list of non-words). Task 1_2 (e.g., identify unique words) has similar task execution information as task 1_1 to produce task 1_2 intermediate results (R1-2, which is the list of unique words).

Task 1_3 (e.g., translate) includes task execution information as being non-ordered (i.e., is independent), having DT execution modules 1_1, 2_1, 3_1, 4_1, and 5_1 translate data partitions 2_1 through 2_4 and having DT execution modules 1_2, 2_2, 3_2, 4_2, and 5_2 translate data partitions 2_5 through 2_z to produce task 1_3 intermediate results (R1-3, which is the translated data). In this example, the data partitions are grouped, where different sets of DT execution modules perform a distributed sub-task (or task) on each data partition group, which allows for further parallel processing.

Task 1_4 (e.g., translate back) is ordered after task 1_3 and is to be executed on task 1_3's intermediate result (e.g., R1-3_1) (e.g., the translated data). DT execution modules 1_1, 2_1, 3_1, 4_1, and 5_1 are allocated to translate back task 1_3 intermediate result partitions R1-3_1 through R1-3_4 and DT execution modules 1_2, 2_2, 6_1, 7_1, and 7_2 are allocated to translate back task 1_3 intermediate result partitions R1-3_5 through R1-3_z to produce task 1-4 intermediate results (R1-4, which is the translated back data).

Task 1_5 (e.g., compare data and translated data to identify translation errors) is ordered after task 1_4 and is to be executed on task 1_4's intermediate results (R4-1) and on the data. DT execution modules 1_1, 2_1, 3_1, 4_1, and 5_1 are allocated to compare the data partitions (2_1 through 2_z) with partitions of task 1-4 intermediate results partitions R1-4_1 through R1-4_z to produce task 1_5 intermediate results (R1-5, which is the list words translated incorrectly).

Task 1_6 (e.g., determine non-word translation errors) is ordered after tasks 1_1 and 1_5 and is to be executed on tasks 1_1's and 1_5's intermediate results (R1-1 and R1-5). DT execution modules 1_1, 2_1, 3_1, 4_1, and 5_1 are allocated to compare the partitions of task 1_1 intermediate results (R1-1_1 through R1-1_z) with partitions of task 1-5 intermediate results partitions (R1-5_1 through R1-5_z) to produce task 1_6 intermediate results (R1-6, which is the list translation errors due to non-words).

Task 1_7 (e.g., determine words correctly translated) is ordered after tasks 1_2 and 1_5 and is to be executed on tasks 1_2's and 1_5's intermediate results (R1-1 and R1-5). DT execution modules 1_2, 2_2, 3_2, 4_2, and 5_2 are allocated to compare the partitions of task 1_2 intermediate results (R1-2_1 through R1-2_z) with partitions of task 1-5 intermediate results partitions (R1-5_1 through R1-5_z) to produce task 1_7 intermediate results (R1-7, which is the list of correctly translated words).

Task 2 (e.g., find specific words and/or phrases) has no task ordering (i.e., is independent of the results of other sub-tasks), is to be performed on data partitions 2_1 through 2_z by DT execution modules 3_1, 4_1, 5_1, 6_1, and 7_1. For instance, DT execution modules 3_1, 4_1, 5_1, 6_1, and 7_1 search for specific words and/or phrases in data partitions 2_1 through 2_z to produce task 2 intermediate results (R2, which is a list of specific words and/or phrases).

Task 3_2 (e.g., find specific translated words and/or phrases) is ordered after task 1_3 (e.g., translate) is to be performed on partitions R1-3_1 through R1-3_z by DT execution modules 1_2, 2_2, 3_2, 4_2, and 5_2. For instance, DT execution modules 1_2, 2_2, 3_2, 4_2, and 5_2 search for specific translated words and/or phrases in the partitions of the translated data (R1-3_1 through R1-3_z) to produce task 3_2 intermediate results (R3-2, which is a list of specific translated words and/or phrases).

For each task, the intermediate result information indicates which DST unit is responsible for overseeing execution of the task and, if needed, processing the partial results generated by the set of allocated DT execution units. In addition, the intermediate result information indicates a scratch pad memory for the task and where the corresponding intermediate results are to be stored. For example, for intermediate result R1-1 (the intermediate result of task 1_1), DST unit 1 is responsible for overseeing execution of the task 1_1 and coordinates storage of the intermediate result as encoded intermediate result slices stored in memory of DST execution units 1-5. In general, the scratch pad is for storing non-DS encoded intermediate results and the intermediate result storage is for storing DS encoded intermediate results.

FIGS. 33-38 are schematic block diagrams of the distributed storage and task network (DSTN) module performing the example of FIG. 30. In FIG. 33, the DSTN module accesses the data 92 and partitions it into a plurality of partitions 1-z in accordance with distributed storage and task network (DST) allocation information. For each data partition, the DSTN identifies a set of its DT (distributed task) execution modules 90 to perform the task (e.g., identify non-words (i.e., not in a reference dictionary) within the data partition) in accordance with the DST allocation information. From data partition to data partition, the set of DT execution modules 90 may be the same, different, or a combination thereof (e.g., some data partitions use the same set while other data partitions use different sets).

For the first data partition, the first set of DT execution modules (e.g., 1_1, 2_1, 3_1, 4_1, and 5_1 per the DST allocation information of FIG. 32) executes task 1_1 to produce a first partial result 102 of non-words found in the first data partition. The second set of DT execution modules (e.g., 1_1, 2_1, 3_1, 4_1, and 5_1 per the DST allocation information of FIG. 32) executes task 1_1 to produce a second partial result 102 of non-words found in the second data partition. The sets of DT execution modules (as per the DST allocation information) perform task 1_1 on the data partitions until the “z” set of DT execution modules performs task 1_1 on the “zth” data partition to produce a “zth” partial result 102 of non-words found in the “zth” data partition.

As indicated in the DST allocation information of FIG. 32, DST execution unit 1 is assigned to process the first through “zth” partial results to produce the first intermediate result (R1-1), which is a list of non-words found in the data. For instance, each set of DT execution modules 90 stores its respective partial result in the scratchpad memory of DST execution unit 1 (which is identified in the DST allocation or may be determined by DST execution unit 1). A processing module of DST execution 1 is engaged to aggregate the first through “zth” partial results to produce the first intermediate result (e.g., R1_1). The processing module stores the first intermediate result as non-DS error encoded data in the scratchpad memory or in another section of memory of DST execution unit 1.

DST execution unit 1 engages its DST client module to slice grouping based DS error encode the first intermediate result (e.g., the list of non-words). To begin the encoding, the DST client module determines whether the list of non-words is of a sufficient size to partition (e.g., greater than a Terabyte). If yes, it partitions the first intermediate result (R1-1) into a plurality of partitions (e.g., R1-1_1 through R1-1_m). If the first intermediate result is not of sufficient size to partition, it is not partitioned.

For each partition of the first intermediate result, or for the first intermediate result, the DST client module uses the DS error encoding parameters of the data (e.g., DS parameters of data 2, which includes 3/5 decode threshold/pillar width ratio) to produce slice groupings. The slice groupings are stored in the intermediate result memory (e.g., allocated memory in the memories of DST execution units 1-5).

In FIG. 34, the DSTN module is performing task 1_2 (e.g., find unique words) on the data 92. To begin, the DSTN module accesses the data 92 and partitions it into a plurality of partitions 1-z in accordance with the DST allocation information or it may use the data partitions of task 1_1 if the partitioning is the same. For each data partition, the DSTN identifies a set of its DT execution modules to perform task 1_2 in accordance with the DST allocation information. From data partition to data partition, the set of DT execution modules may be the same, different, or a combination thereof. For the data partitions, the allocated set of DT execution modules executes task 1_2 to produce a partial results (e.g., 1^(st) through “zth”) of unique words found in the data partitions.

As indicated in the DST allocation information of FIG. 32, DST execution unit 1 is assigned to process the first through “zth” partial results 102 of task 1_2 to produce the second intermediate result (R1-2), which is a list of unique words found in the data 92. The processing module of DST execution 1 is engaged to aggregate the first through “zth” partial results of unique words to produce the second intermediate result. The processing module stores the second intermediate result as non-DS error encoded data in the scratchpad memory or in another section of memory of DST execution unit 1.

DST execution unit 1 engages its DST client module to slice grouping based DS error encode the second intermediate result (e.g., the list of non-words). To begin the encoding, the DST client module determines whether the list of unique words is of a sufficient size to partition (e.g., greater than a Terabyte). If yes, it partitions the second intermediate result (R1-2) into a plurality of partitions (e.g., R1-2_1 through R1-2_m). If the second intermediate result is not of sufficient size to partition, it is not partitioned.

For each partition of the second intermediate result, or for the second intermediate results, the DST client module uses the DS error encoding parameters of the data (e.g., DS parameters of data 2, which includes 3/5 decode threshold/pillar width ratio) to produce slice groupings. The slice groupings are stored in the intermediate result memory (e.g., allocated memory in the memories of DST execution units 1-5).

In FIG. 35, the DSTN module is performing task 1_3 (e.g., translate) on the data 92. To begin, the DSTN module accesses the data 92 and partitions it into a plurality of partitions 1-z in accordance with the DST allocation information or it may use the data partitions of task 1_1 if the partitioning is the same. For each data partition, the DSTN identifies a set of its DT execution modules to perform task 1_3 in accordance with the DST allocation information (e.g., DT execution modules 1_1, 2_1, 3_1, 4_1, and 5_1 translate data partitions 2_1 through 2_4 and DT execution modules 1_2, 2_2, 3_2, 4_2, and 5_2 translate data partitions 2_5 through 2_z). For the data partitions, the allocated set of DT execution modules 90 executes task 1_3 to produce partial results 102 (e.g., 1^(st) through “zth”) of translated data.

As indicated in the DST allocation information of FIG. 32, DST execution unit 2 is assigned to process the first through “zth” partial results of task 1_3 to produce the third intermediate result (R1-3), which is translated data. The processing module of DST execution 2 is engaged to aggregate the first through “zth” partial results of translated data to produce the third intermediate result. The processing module stores the third intermediate result as non-DS error encoded data in the scratchpad memory or in another section of memory of DST execution unit 2.

DST execution unit 2 engages its DST client module to slice grouping based DS error encode the third intermediate result (e.g., translated data). To begin the encoding, the DST client module partitions the third intermediate result (R1-3) into a plurality of partitions (e.g., R1-3_1 through R1-3_y). For each partition of the third intermediate result, the DST client module uses the DS error encoding parameters of the data (e.g., DS parameters of data 2, which includes 3/5 decode threshold/pillar width ratio) to produce slice groupings. The slice groupings are stored in the intermediate result memory (e.g., allocated memory in the memories of DST execution units 2-6 per the DST allocation information).

As is further shown in FIG. 35, the DSTN module is performing task 1_4 (e.g., retranslate) on the translated data of the third intermediate result. To begin, the DSTN module accesses the translated data (from the scratchpad memory or from the intermediate result memory and decodes it) and partitions it into a plurality of partitions in accordance with the DST allocation information. For each partition of the third intermediate result, the DSTN identifies a set of its DT execution modules 90 to perform task 1_4 in accordance with the DST allocation information (e.g., DT execution modules 1_1, 2_1, 3_1, 4_1, and 5_1 are allocated to translate back partitions R1-3_1 through R1-3_4 and DT execution modules 1_2, 2_2, 6_1, 7_1, and 7_2 are allocated to translate back partitions R1-3_5 through R1-3_z). For the partitions, the allocated set of DT execution modules executes task 1_4 to produce partial results 102 (e.g., 1^(st) through “zth”) of re-translated data.

As indicated in the DST allocation information of FIG. 32, DST execution unit 3 is assigned to process the first through “zth” partial results of task 1_4 to produce the fourth intermediate result (R1-4), which is retranslated data. The processing module of DST execution 3 is engaged to aggregate the first through “zth” partial results of retranslated data to produce the fourth intermediate result. The processing module stores the fourth intermediate result as non-DS error encoded data in the scratchpad memory or in another section of memory of DST execution unit 3.

DST execution unit 3 engages its DST client module to slice grouping based DS error encode the fourth intermediate result (e.g., retranslated data). To begin the encoding, the DST client module partitions the fourth intermediate result (R1-4) into a plurality of partitions (e.g., R1-4_1 through R1-4_z). For each partition of the fourth intermediate result, the DST client module uses the DS error encoding parameters of the data (e.g., DS parameters of data 2, which includes 3/5 decode threshold/pillar width ratio) to produce slice groupings. The slice groupings are stored in the intermediate result memory (e.g., allocated memory in the memories of DST execution units 3-7 per the DST allocation information).

In FIG. 36, a distributed storage and task network (DSTN) module is performing task 1_5 (e.g., compare) on data 92 and retranslated data of FIG. 35. To begin, the DSTN module accesses the data 92 and partitions it into a plurality of partitions in accordance with the DST allocation information or it may use the data partitions of task 1_1 if the partitioning is the same. The DSTN module also accesses the retranslated data from the scratchpad memory, or from the intermediate result memory and decodes it, and partitions it into a plurality of partitions in accordance with the DST allocation information. The number of partitions of the retranslated data corresponds to the number of partitions of the data.

For each pair of partitions (e.g., data partition 1 and retranslated data partition 1), the DSTN identifies a set of its DT execution modules 90 to perform task 1_5 in accordance with the DST allocation information (e.g., DT execution modules 1_1, 2_1, 3_1, 4_1, and 5_1). For each pair of partitions, the allocated set of DT execution modules executes task 1_5 to produce partial results 102 (e.g., 1^(st) through “zth”) of a list of incorrectly translated words and/or phrases.

As indicated in the DST allocation information of FIG. 32, DST execution unit 1 is assigned to process the first through “zth” partial results of task 1_5 to produce the fifth intermediate result (R1-5), which is the list of incorrectly translated words and/or phrases. In particular, the processing module of DST execution 1 is engaged to aggregate the first through “zth” partial results of the list of incorrectly translated words and/or phrases to produce the fifth intermediate result. The processing module stores the fifth intermediate result as non-DS error encoded data in the scratchpad memory or in another section of memory of DST execution unit 1.

DST execution unit 1 engages its DST client module to slice grouping based DS error encode the fifth intermediate result. To begin the encoding, the DST client module partitions the fifth intermediate result (R1-5) into a plurality of partitions (e.g., R1-5_1 through R1-5_z). For each partition of the fifth intermediate result, the DST client module uses the DS error encoding parameters of the data (e.g., DS parameters of data 2, which includes 3/5 decode threshold/pillar width ratio) to produce slice groupings. The slice groupings are stored in the intermediate result memory (e.g., allocated memory in the memories of DST execution units 1-5 per the DST allocation information).

As is further shown in FIG. 36, the DSTN module is performing task 1_6 (e.g., translation errors due to non-words) on the list of incorrectly translated words and/or phrases (e.g., the fifth intermediate result R1-5) and the list of non-words (e.g., the first intermediate result R1-1). To begin, the DSTN module accesses the lists and partitions them into a corresponding number of partitions.

For each pair of partitions (e.g., partition R1-1_1 and partition R1-5_1), the DSTN identifies a set of its DT execution modules 90 to perform task 1_6 in accordance with the DST allocation information (e.g., DT execution modules 1_1, 2_1, 3_1, 4_1, and 5_1). For each pair of partitions, the allocated set of DT execution modules executes task 1_6 to produce partial results 102 (e.g., 1^(st) through “zth”) of a list of incorrectly translated words and/or phrases due to non-words.

As indicated in the DST allocation information of FIG. 32, DST execution unit 2 is assigned to process the first through “zth” partial results of task 1_6 to produce the sixth intermediate result (R1-6), which is the list of incorrectly translated words and/or phrases due to non-words. In particular, the processing module of DST execution 2 is engaged to aggregate the first through “zth” partial results of the list of incorrectly translated words and/or phrases due to non-words to produce the sixth intermediate result. The processing module stores the sixth intermediate result as non-DS error encoded data in the scratchpad memory or in another section of memory of DST execution unit 2.

DST execution unit 2 engages its DST client module to slice grouping based DS error encode the sixth intermediate result. To begin the encoding, the DST client module partitions the sixth intermediate result (R1-6) into a plurality of partitions (e.g., R1-6_1 through R1-6_z). For each partition of the sixth intermediate result, the DST client module uses the DS error encoding parameters of the data (e.g., DS parameters of data 2, which includes 3/5 decode threshold/pillar width ratio) to produce slice groupings. The slice groupings are stored in the intermediate result memory (e.g., allocated memory in the memories of DST execution units 2-6 per the DST allocation information).

As is still further shown in FIG. 36, the DSTN module is performing task 1_7 (e.g., correctly translated words and/or phrases) on the list of incorrectly translated words and/or phrases (e.g., the fifth intermediate result R1-5) and the list of unique words (e.g., the second intermediate result R1-2). To begin, the DSTN module accesses the lists and partitions them into a corresponding number of partitions.

For each pair of partitions (e.g., partition R1-2_1 and partition R1-5_1), the DSTN identifies a set of its DT execution modules 90 to perform task 1_7 in accordance with the DST allocation information (e.g., DT execution modules 1_2, 2_2, 3_2, 4_2, and 5_2). For each pair of partitions, the allocated set of DT execution modules executes task 1_7 to produce partial results 102 (e.g., 1^(st) through “zth”) of a list of correctly translated words and/or phrases.

As indicated in the DST allocation information of FIG. 32, DST execution unit 3 is assigned to process the first through “zth” partial results of task 1_7 to produce the seventh intermediate result (R1-7), which is the list of correctly translated words and/or phrases. In particular, the processing module of DST execution 3 is engaged to aggregate the first through “zth” partial results of the list of correctly translated words and/or phrases to produce the seventh intermediate result. The processing module stores the seventh intermediate result as non-DS error encoded data in the scratchpad memory or in another section of memory of DST execution unit 3.

DST execution unit 3 engages its DST client module to slice grouping based DS error encode the seventh intermediate result. To begin the encoding, the DST client module partitions the seventh intermediate result (R1-7) into a plurality of partitions (e.g., R1-7_1 through R1-7_z). For each partition of the seventh intermediate result, the DST client module uses the DS error encoding parameters of the data (e.g., DS parameters of data 2, which includes 3/5 decode threshold/pillar width ratio) to produce slice groupings. The slice groupings are stored in the intermediate result memory (e.g., allocated memory in the memories of DST execution units 3-7 per the DST allocation information).

In FIG. 37, the distributed storage and task network (DSTN) module is performing task 2 (e.g., find specific words and/or phrases) on the data 92. To begin, the DSTN module accesses the data and partitions it into a plurality of partitions 1-z in accordance with the DST allocation information or it may use the data partitions of task 1_1 if the partitioning is the same. For each data partition, the DSTN identifies a set of its DT execution modules 90 to perform task 2 in accordance with the DST allocation information. From data partition to data partition, the set of DT execution modules may be the same, different, or a combination thereof. For the data partitions, the allocated set of DT execution modules executes task 2 to produce partial results 102 (e.g., 1^(st) through “zth”) of specific words and/or phrases found in the data partitions.

As indicated in the DST allocation information of FIG. 32, DST execution unit 7 is assigned to process the first through “zth” partial results of task 2 to produce task 2 intermediate result (R2), which is a list of specific words and/or phrases found in the data. The processing module of DST execution 7 is engaged to aggregate the first through “zth” partial results of specific words and/or phrases to produce the task 2 intermediate result. The processing module stores the task 2 intermediate result as non-DS error encoded data in the scratchpad memory or in another section of memory of DST execution unit 7.

DST execution unit 7 engages its DST client module to slice grouping based DS error encode the task 2 intermediate result. To begin the encoding, the DST client module determines whether the list of specific words and/or phrases is of a sufficient size to partition (e.g., greater than a Terabyte). If yes, it partitions the task 2 intermediate result (R2) into a plurality of partitions (e.g., R2_1 through R2_m). If the task 2 intermediate result is not of sufficient size to partition, it is not partitioned.

For each partition of the task 2 intermediate result, or for the task 2 intermediate results, the DST client module uses the DS error encoding parameters of the data (e.g., DS parameters of data 2, which includes 3/5 decode threshold/pillar width ratio) to produce slice groupings. The slice groupings are stored in the intermediate result memory (e.g., allocated memory in the memories of DST execution units 1-4, and 7).

In FIG. 38, the distributed storage and task network (DSTN) module is performing task 3 (e.g., find specific translated words and/or phrases) on the translated data (R1-3). To begin, the DSTN module accesses the translated data (from the scratchpad memory or from the intermediate result memory and decodes it) and partitions it into a plurality of partitions in accordance with the DST allocation information. For each partition, the DSTN identifies a set of its DT execution modules to perform task 3 in accordance with the DST allocation information. From partition to partition, the set of DT execution modules may be the same, different, or a combination thereof. For the partitions, the allocated set of DT execution modules 90 executes task 3 to produce partial results 102 (e.g., 1^(st) through “zth”) of specific translated words and/or phrases found in the data partitions.

As indicated in the DST allocation information of FIG. 32, DST execution unit 5 is assigned to process the first through “zth” partial results of task 3 to produce task 3 intermediate result (R3), which is a list of specific translated words and/or phrases found in the translated data. In particular, the processing module of DST execution 5 is engaged to aggregate the first through “zth” partial results of specific translated words and/or phrases to produce the task 3 intermediate result. The processing module stores the task 3 intermediate result as non-DS error encoded data in the scratchpad memory or in another section of memory of DST execution unit 7.

DST execution unit 5 engages its DST client module to slice grouping based DS error encode the task 3 intermediate result. To begin the encoding, the DST client module determines whether the list of specific translated words and/or phrases is of a sufficient size to partition (e.g., greater than a Terabyte). If yes, it partitions the task 3 intermediate result (R3) into a plurality of partitions (e.g., R3_1 through R3_m). If the task 3 intermediate result is not of sufficient size to partition, it is not partitioned.

For each partition of the task 3 intermediate result, or for the task 3 intermediate results, the DST client module uses the DS error encoding parameters of the data (e.g., DS parameters of data 2, which includes 3/5 decode threshold/pillar width ratio) to produce slice groupings. The slice groupings are stored in the intermediate result memory (e.g., allocated memory in the memories of DST execution units 1-4, 5, and 7).

FIG. 39 is a diagram of an example of combining result information into final results 104 for the example of FIG. 30. In this example, the result information includes the list of specific words and/or phrases found in the data (task 2 intermediate result), the list of specific translated words and/or phrases found in the data (task 3 intermediate result), the list of non-words found in the data (task 1 first intermediate result R1-1), the list of unique words found in the data (task 1 second intermediate result R1-2), the list of translation errors due to non-words (task 1 sixth intermediate result R1-6), and the list of correctly translated words and/or phrases (task 1 seventh intermediate result R1-7). The task distribution module provides the result information to the requesting DST client module as the results 104.

FIG. 40A is a schematic block diagram of an embodiment of a decentralized agreement module 350 that includes a set of deterministic functions 1-N, a set of normalizing functions 1-N, a set of scoring functions 1-N, and a ranking function 352. Each of the deterministic function, the normalizing function, the scoring function, and the ranking function 352, may be implemented utilizing the processing module 84 of FIG. 3. The decentralized agreement module 350 may be implemented utilizing any module and/or unit of a dispersed storage network (DSN). For example, the decentralized agreement module is implemented utilizing the distributed storage and task (DST) client module 34 of FIG. 1.

The decentralized agreement module 350 functions to receive a ranked scoring information request 354 and to generate ranked scoring information 358 based on the ranked scoring information request 354 and other information. The ranked scoring information request 354 includes one or more of an asset identifier (ID) 356 of an asset associated with the request, an asset type indicator, one or more location identifiers of locations associated with the DSN, one or more corresponding location weights, and a requesting entity ID. The asset includes any portion of data associated with the DSN including one or more asset types including a data object, a data record, an encoded data slice, a data segment, a set of encoded data slices, and a plurality of sets of encoded data slices. As such, the asset ID 356 of the asset includes one or more of a data name, a data record identifier, a source name, a slice name, and a plurality of sets of slice names.

Each location of the DSN includes an aspect of a DSN resource. Examples of locations includes one or more of a storage unit, a memory device of the storage unit, a site, a storage pool of storage units, a pillar index associated with each encoded data slice of a set of encoded data slices generated by an information dispersal algorithm (IDA), a DST client module 34 of FIG. 1, a DST processing unit 16 of FIG. 1, a DST integrity processing unit 20 of FIG. 1, a DSTN managing unit 18 of FIG. 1, a user device 12 of FIG. 1, and a user device 14 of FIG. 1.

Each location is associated with a location weight based on one or more of a resource prioritization of utilization scheme and physical configuration of the DSN. The location weight includes an arbitrary bias which adjusts a proportion of selections to an associated location such that a probability that an asset will be mapped to that location is equal to the location weight divided by a sum of all location weights for all locations of comparison. For example, each storage pool of a plurality of storage pools is associated with a location weight based on storage capacity. For instance, storage pools with more storage capacity are associated with higher location weights than others. The other information may include a set of location identifiers and a set of location weights associated with the set of location identifiers. For example, the other information includes location identifiers and location weights associated with a set of memory devices of a storage unit when the requesting entity utilizes the decentralized agreement module 350 to produce ranked scoring information 358 with regards to selection of a memory device of the set of memory devices for accessing a particular encoded data slice (e.g., where the asset ID includes a slice name of the particular encoded data slice).

The decentralized agreement module 350 outputs substantially identical ranked scoring information for each ranked scoring information request that includes substantially identical content of the ranked scoring information request. For example, a first requesting entity issues a first ranked scoring information request to the decentralized agreement module 350 and receives first ranked scoring information. A second requesting entity issues a second ranked scoring information request to the decentralized agreement module and receives second ranked scoring information. The second ranked scoring information is substantially the same as the first ranked scoring information when the second ranked scoring information request is substantially the same as the first ranked scoring information request.

As such, two or more requesting entities may utilize the decentralized agreement module 350 to determine substantially identical ranked scoring information. As a specific example, the first requesting entity selects a first storage pool of a plurality of storage pools for storing a set of encoded data slices utilizing the decentralized agreement module 350 and the second requesting entity identifies the first storage pool of the plurality of storage pools for retrieving the set of encoded data slices utilizing the decentralized agreement module 350.

In an example of operation, the decentralized agreement module 350 receives the ranked scoring information request 354. Each deterministic function performs a deterministic function on a combination and/or concatenation (e.g., add, append, interleave) of the asset ID 356 of the ranked scoring information request 354 and an associated location ID of the set of location IDs to produce an interim result. The deterministic function includes at least one of a hashing function, a hash-based message authentication code function, a mask generating function, a cyclic redundancy code function, hashing module of a number of locations, consistent hashing, rendezvous hashing, and a sponge function. As a specific example, deterministic function 2 appends a location ID 2 of a storage pool 2 to a source name as the asset ID to produce a combined value and performs the mask generating function on the combined value to produce interim result 2.

With a set of interim results 1-N, each normalizing function performs a normalizing function on a corresponding interim result to produce a corresponding normalized interim result. The performing of the normalizing function includes dividing the interim result by a number of possible permutations of the output of the deterministic function to produce the normalized interim result. For example, normalizing function 2 performs the normalizing function on the interim result 2 to produce a normalized interim result 2.

With a set of normalized interim results 1-N, each scoring function performs a scoring function on a corresponding normalized interim result to produce a corresponding score. The performing of the scoring function includes dividing an associated location weight by a negative log of the normalized interim result. For example, scoring function 2 divides location weight 2 of the storage pool 2 (e.g., associated with location ID 2) by a negative log of the normalized interim result 2 to produce a score 2.

With a set of scores 1-N, the ranking function 352 performs a ranking function on the set of scores 1-N to generate the ranked scoring information 358. The ranking function includes rank ordering each score with other scores of the set of scores 1-N, where a highest score is ranked first. As such, a location associated with the highest score may be considered a highest priority location for resource utilization (e.g., accessing, storing, retrieving, etc., the given asset of the request). Having generated the ranked scoring information 358, the decentralized agreement module 350 outputs the ranked scoring information 358 to the requesting entity.

FIG. 40B is a flowchart illustrating an example of selecting a resource. The method begins or continues at step 360 where a processing module (e.g., of a decentralized agreement module) receives a ranked scoring information request from a requesting entity with regards to a set of candidate resources. For each candidate resource, the method continues at step 362 where the processing module performs a deterministic function on a location identifier (ID) of the candidate resource and an asset ID of the ranked scoring information request to produce an interim result. As a specific example, the processing module combines the asset ID and the location ID of the candidate resource to produce a combined value and performs a hashing function on the combined value to produce the interim result.

For each interim result, the method continues at step 364 where the processing module performs a normalizing function on the interim result to produce a normalized interim result. As a specific example, the processing module obtains a permutation value associated with the deterministic function (e.g., maximum number of permutations of output of the deterministic function) and divides the interim result by the permutation value to produce the normalized interim result (e.g., with a value between 0 and 1).

For each normalized interim result, the method continues at step 366 where the processing module performs a scoring function on the normalized interim result utilizing a location weight associated with the candidate resource associated with the interim result to produce a score of a set of scores. As a specific example, the processing module divides the location weight by a negative log of the normalized interim result to produce the score.

The method continues at step 368 where the processing module rank orders the set of scores to produce ranked scoring information (e.g., ranking a highest value first). The method continues at step 370 where the processing module outputs the ranked scoring information to the requesting entity. The requesting entity may utilize the ranked scoring information to select one location of a plurality of locations.

FIG. 40C is a schematic block diagram of an embodiment of a dispersed storage network (DSN) that includes the distributed storage and task (DST) processing unit 16 of FIG. 1, the network 24 of FIG. 1, and the distributed storage and task network (DSTN) module 22 of FIG. 1. Hereafter, the DSTN module 22 may be interchangeably referred to as a DSN memory. The DST processing unit 16 includes a decentralized agreement module 380 and the DST client module 34 of FIG. 1. The decentralized agreement module 380 be implemented utilizing the decentralized agreement module 350 of FIG. 40A. The DSTN module 22 includes a plurality of DST execution (EX) unit pools 1-P. Each DST execution unit pool includes one or more sites 1-S. Each site includes one or more DST execution units 1-N. Each DST execution unit may be associated with at least one pillar of N pillars associated with an information dispersal algorithm (IDA), where a data segment is dispersed storage error encoded using the IDA to produce one or more sets of encoded data slices, and where each set includes N encoded data slices and like encoded data slices (e.g., slice 3's) of two or more sets of encoded data slices are included in a common pillar (e.g., pillar 3). Each site may not include every pillar and a given pillar may be implemented at more than one site. Each DST execution unit includes a plurality of memories 1-M. Each DST execution unit may be implemented utilizing the DST execution unit 36 of FIG. 1. Hereafter, a DST execution unit may be referred to interchangeably as a storage unit and a set of DST execution units may be interchangeably referred to as a set of storage units and/or as a storage unit set.

The DSN functions to receive data access requests 382, select resources of at least one DST execution unit pool for data access, utilize the selected DST execution unit pool for the data access, and issue a data access response 392 based on the data access. The selecting of the resources includes utilizing a decentralized agreement function of the decentralized agreement module 380, where a plurality of locations are ranked against each other. The selecting may include selecting one storage pool of the plurality of storage pools, selecting DST execution units at various sites of the plurality of sites, selecting a memory of the plurality of memories for each DST execution unit, and selecting combinations of memories, DST execution units, sites, pillars, and storage pools.

In an example of operation, the DST client module 34 receives the data access request 382 from a requesting entity, where the data access request 382 includes at least one of a store data request, a retrieve data request, a delete data request, a data name, and a requesting entity identifier (ID). Having received the data access request 382, the DST client module 34 determines a DSN address associated with the data access request. The DSN address includes at least one of a source name (e.g., including a vault ID and an object number associated with the data name), a data segment ID, a set of slice names, a plurality of sets of slice names. The determining includes at least one of generating (e.g., for the store data request) and retrieving (e.g., from a DSN directory, from a dispersed hierarchical index) based on the data name (e.g., for the retrieve data request).

Having determined the DSN address, the DST client module 34 selects a plurality of resource levels (e.g., DST EX unit pool, site, DST execution unit, pillar, memory) associated with the DSTN module 22. The determining may be based on one or more of the data name, the requesting entity ID, a predetermination, a lookup, a DSN performance indicator, and interpreting an error message. For example, the DST client module 34 selects the DST execution unit pool as a first resource level and a set of memory devices of a plurality of memory devices as a second resource level based on a system registry lookup for a vault associated with the requesting entity.

Having selected the plurality of resource levels, the DST client module 34, for each resource level, issues a ranked scoring information request 384 to the decentralized agreement module 380 utilizing the DSN address as an asset ID. The decentralized agreement module 380 performs the decentralized agreement function based on the asset ID (e.g., the DSN address), identifiers of locations of the selected resource levels, and location weights of the locations to generate ranked scoring information 386.

For each resource level, the DST client module 34 receives corresponding ranked scoring information 386. Having received the ranked scoring information 386, the DST client module 34 identifies one or more resources associated with the resource level based on the rank scoring information 386. For example, the DST client module 34 identifies a DST execution unit pool associated with a highest score and identifies a set of memory devices within DST execution units of the identified DST execution unit pool with a highest score.

Having identified the one or more resources, the DST client module 34 accesses the DSTN module 22 based on the identified one or more resources associated with each resource level. For example, the DST client module 34 issues resource access requests 388 (e.g., write slice requests when storing data, read slice requests when recovering data) to the identified DST execution unit pool, where the resource access requests 388 further identify the identified set of memory devices. Having accessed the DSTN module 22, the DST client module 34 receives resource access responses 390 (e.g., write slice responses, read slice responses). The DST client module 34 issues the data access response 392 based on the received resource access responses 390. For example, the DST client module 34 decodes received encoded data slices to reproduce data and generates the data access response 392 to include the reproduced data.

FIG. 40D is a flowchart illustrating an example of accessing a dispersed storage network (DSN) memory. The method begins or continues at step 394 where a processing module (e.g., of a distributed storage and task (DST) client module) receives a data access request from a requesting entity. The data access request includes one or more of a storage request, a retrieval request, a requesting entity identifier, and a data identifier (ID). The method continues at step 396 where the processing module determines a DSN address associated with the data access request. For example, the processing module generates the DSN address for the storage request. As another example, the processing module performs a lookup for the retrieval request based on the data identifier.

The method continues at step 398 where the processing module selects a plurality of resource levels associated with the DSN memory. The selecting may be based on one or more of a predetermination, a range of weights associated with available resources, a resource performance level, and a resource performance requirement level. For each resource level, the method continues at step 400 where the processing module determines ranked scoring information. For example, the processing module issues a ranked scoring information request to a decentralized agreement module based on the DSN address and receives corresponding ranked scoring information for the resource level, where the decentralized agreement module performs a decentralized agreement protocol function on the DSN address using the associated resource identifiers and resource weights for the resource level to produce the ranked scoring information for the resource level.

For each resource level, the method continues at step 402 where the processing module selects one or more resources associated with the resource level based on the ranked scoring information. For example, the processing module selects a resource associated with a highest score when one resource is required. As another example, the processing module selects a plurality of resources associated with highest scores when a plurality of resources are required.

The method continues at step 404 where the processing module accesses the DSN memory utilizing the selected one or more resources for each of the plurality of resource levels. For example, the processing module identifies network addressing information based on the selected resources including one or more of a storage unit Internet protocol address and a memory device identifier, generates a set of encoded data slice access requests based on the data access request and the DSN address, and sends the set of encoded data slice access requests to the DSN memory utilizing the identified network addressing information.

The method continues at step 406 where the processing module issues a data access response to the requesting entity based on one or more resource access responses from the DSN memory. For example, the processing module issues a data storage status indicator when storing data. As another example, the processing module generates the data access response to include recovered data when retrieving data.

FIG. 41A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) that includes the distributed storage and task (DST) processing unit 16 of FIG. 1, the network 24 of FIG. 1, and a storage vault 410. The DST processing unit 16 includes a decentralized agreement module 412, and the DST client module 34 of FIG. 1. The decentralized agreement module 412 may be implemented utilizing the decentralized agreement module 350 of FIG. 40A. The storage vault includes DST execution (EX) unit pools 1-2. Each DST execution unit pool includes a set of DST execution units 1-n. Each DST execution unit may be implemented utilizing the DST execution unit 36 of FIG. 1. Hereafter, a DST execution unit may be interchangeably referred to as a storage unit and a DST execution unit pool may be interchangeably referred to as a storage pool. The DSN functions to authorize a slice access request.

In an example of operation of the authorizing a slice access request, the DST processing unit 16 receives a data access request 414 to receive data stored as a plurality of sets of encoded data slices in at least one storage pool. Having received the data access request 414, the DST client module 34 identifies the storage pool associated with the storage of the requested data. For example, the DST client module 34 issues a ranked scoring information request 416 to the decentralized agreement module 412, where the ranked scoring information request 416 includes an identifier associated with the data and location weights associated with the storage pools. The decentralized agreement module performs a decentralized agreement protocol function on the identifier associated with the data using location weights to generate a score for each of the storage pools. The decentralized agreement module issues a ranked scoring information 418 to the DST client module 34, where the ranked scoring information 418 includes the scores associated with each of the storage pools. The DST client module 34 identifies a storage pool associated with a highest score of the ranked scoring information as the identified storage pool associated with the storage of the requested data.

Having identified the storage pool associated with the storage of the requested data, the DST client module 34 issues, via the network 24, access requests 420, to the identified storage pool, where the access requests 420 includes one or more sets of read slice requests or one or more sets of write slice requests. For example, the DST client module 34 sends the access requests 420 to the DST execution unit pool 2 when the second storage pool is the identified storage pool. Having received the access request 420, the storage units of the identified storage pool determine that the encoded data slices associated with the access requests are temporarily stored by the other storage pool when a migration is in progress that is migrating the encoded data slices from the other storage pool to the identified storage pool (e.g., a migration is in progress from the DST execution unit pool 1 to the DST execution unit pool 2 in accordance with a recent location weight change for the storage pools). The determining may be based on one or more of interpreting a migration flag, interpreting a query response, accessing a local memory of a storage unit of the identified storage pool.

Having determined that the encoded data slices associated with the access request or temporally stored by the other storage pool, the storage units of the identified storage pool issue, via the network 24, proxied access requests 422 to the other storage pool, where the proxied access requests 422 includes the access requests 420 and identifiers of one or more storage units of the identified storage pool. Storage units of the other storage pool (e.g., pool 1) receiving the proxied access requests 422 from sending storage units of the identified storage pool determine whether the identified storage pool and the other storage pool are associated with a common vault (e.g., the storage vault). The determining may be based on one or more of interpreting system registry information, interpreting a query response, and performing a lookup. For example, a storage unit of the first storage pool interprets the system registry information to determine that a corresponding storage unit of the second storage pool and the storage units are associated with the storage vault (e.g., the common vault).

When the identified storage pool and the other storage pool are associated with a common vault, the receiving storage unit of the other storage pool determines whether a slice name of the proxied access request is associated with a slice name range of a corresponding sending storage unit. The determining may be based on one or more of interpreting the system registry information, a lookup, and interpreting results of utilizing the distributed agreement protocol function on the slice name utilizing location weights of the identified storage pool.

When the slice name is associated with the sending storage unit, the receiving storage unit determines whether an active slice migration process exists to migrate one or more encoded data slices from the other storage pool to the identified storage pool. The determining may be based on one or more of interpreting a migration status indicator, performing a lookup, interpreting a query response, interpreting pending tasks of storage units of the other storage pool (e.g., sending migration slices 426, via the network 24, from the first storage pool to the second storage pool), and interpreting system registry information.

When the active slice migration process is active, the receiving storage unit determines whether the identified storage pool is associated with the slice name utilizing the distributed agreement protocol function. For example, the receiving storage unit verifies that ranked scoring information indicates that the identified storage pool is a highest ranked storage pool with regards to the slice name utilizing current location weights.

When the identified storage pool is associated with the slice name, the receiving storage unit processes the proxied slice access request 422. For example, the receiving storage unit executes the proxied slice access request (e.g., stores a slice when writing, retrieves a slice when reading) to produce an access response 424 (e.g., a writing status indicator, a slice when reading) and issues, via the network 24, the access response 424 to at least one of the corresponding sending storage unit and the DST client module 34.

FIG. 41B is a flowchart illustrating an example of authorizing a slice access request. The method includes step 430 where a storage unit of a set of storage pool receives a slice access request (e.g., of a proxied slice access request) from another storage unit of another storage pool. The receiving may further include identifying the other storage unit and identifying a slice name of the slice access request.

The method continues at step 432 where the storage unit determines whether the storage pool in the other storage pool are associated with a common dispersed storage network (DSN) vault. The determining may include one or more of identifying the storage pool, identifying the other storage pool, interpreting system registry information, and interpreting a query response.

When the storage pool and the other storage pool are associated with the common DSN vault, the method continues at step 434 where the storage unit determines whether a slice name of the slice access request is associated with a slice name range of the other storage unit. The determining includes one or more of interpreting a system registry information and interpreting results of utilizing a distributed agreement protocol function on a slice name utilizing location weights of the storage pool and the other storage pool.

When the slice name of the slice access request is associated with the slice name range of the other storage unit, the method continues at step 436 where the storage unit determines whether an active slice migration process exists between the storage pool and the other storage pool. The determining includes one or more of interpreting a migration status indicator, interpreting the system registry information, and interpreting a query response.

When the active slice migration process exists between the storage pool and the other storage pool, the method continues at step 438 where the storage unit determines whether the other storage pool is associated with the slice name utilizing the distributed agreement protocol function. For example, the storage unit verifies that ranked scoring information indicates that the other storage pool is a highest ranked storage pool with regards to the slice name.

When the other storage pool is associated with the slice name, the method continues at step 440 where the storage unit processes the slice access request. For example, the storage unit executes the slice access request to produce an access response and sends the access response to at least one of the other storage unit and a requesting entity (e.g., the other storage unit).

FIG. 42A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) that includes the distributed storage and task (DST) integrity processing unit 20 of FIG. 1, the network 24 of FIG. 1, and at least two DST execution (EX) unit pools 1-2, etc. Each DST execution unit pool includes a set of DST execution units 1-n. Each DST execution unit includes a decentralized agreement module 450, the DST client module 34 of FIG. 1, and the memory 88 of FIG. 3. The decentralized agreement module 450 may be implemented utilizing the decentralized agreement module 350 of FIG. 40A. Each DST execution unit may be implemented utilizing the DST execution unit 36 of FIG. 1. Hereafter, a DST execution unit may be interchangeably referred to as a storage unit and a DST execution unit pool may be interchangeably referred to as a storage pool. The DSN functions to determine status of a slice migration.

In an example of operation of the determining of the status of the slice migration, a storage unit (e.g., the DST client module 34 of the DST execution unit 1 of the DST execution unit storage pool 1) determines to analyze a slice name range with regards to potential storage of an out-of-place encoded data slice. The determining includes at least one of receiving a list slice request that includes the slice name range, interpreting an analysis schedule, and receiving a slice access request for an encoded data slice associated with a slice name within the slice name range. For example, the DST execution unit 1 of the first storage pool receives, via the network 24, a list request 1 of list slice requests 452 from the DST integrity processing unit 20.

When analyzing the slice name range, the storage unit detects presence of an encoded data slice within a storage unit of a storage pool that includes the storage unit where the encoded data slice is associated with a slice name within the slice name range. The detecting includes at least one of interpreting a local slice name list of encoded data slices stored in a local memory (e.g., memory 88) and verifying integrity of the retrieved encoded data slice (e.g., comparing a stored integrity value of the encoded data slice with a calculated integrity value of the encoded data slice).

Having detected the presence of the encoded data slice of the slice name range, the storage unit performs a decentralized agreement protocol function on the slice name with regards to the plurality of storage pools produces ranked scoring information, where the plurality of storage pools includes the storage pool associated with the storage unit. For example, the DST client module 34 of the DST execution unit 1 of the DST execution unit pool 1 utilizes the decentralized agreement module 450 to perform the decentralized agreement protocol function on the slice name using location weights of the first and second storage pools to produce the ranked scoring information that includes scores for the first and second storage pools.

Having produced the ranked scoring information, the storage unit identifies a storage pool associated with the encoded data slice based on the ranked scoring information. For example, the storage unit identifies a storage pool associated with a highest score of the ranked scoring information. When the identified storage pool is not substantially the same as the storage pool associated with the storage unit, the storage unit indicates that the encoded data slice is the out-of-place encoded data slice. For example, the storage unit issues, via the network 24, slice status 454 to the DST integrity processing unit 20, where the slice status (e.g., a list slice response) includes one or more of slice names and the revision levels of encoded data slices found in the memory 88 of the storage unit, and indicator for each encoded data slice that indicates whether the encoded data slice belongs in the associated storage pool based on utilizing the distributed agreement protocol function (e.g., not “clean” when an out of place slices detected).

When at least one storage pool of these clarity of storage pools indicates the out-of-place encoded data slice within a verification cycle (e.g., a list slice can cycle, a predetermined time frame), the DST integrity processing unit 20 indicates that the migration is not complete. For example, the DST integrity processing unit 20 outputs migration status 456 indicating that the migration is still active. Alternatively, when each storage pool indicates an absence of out-of-place encoded data slices within the verification cycle, the DST integrity processing unit 20 issues migration status 456 that indicates that the migration has completed (e.g., no encoded data slices of all of the storage pools are out-of-place).

FIG. 42B is a flowchart illustrating an example of determining status of the slice migration. The method includes step 460 where a processing module (e.g., of a distributed storage and task (DST) client module) determines to analyze a slice name range with regards to storage of an out-of-place encoded data slice. The determining includes at least one of receiving a list slice requests that includes the slice name range, interpreting an analysis schedule, and receiving a slice access request for a requested slice name of the slice name range.

The method continues at step 462 where the processing module detects presence of an encoded data slice of the storage pool, where the encoded data slices associated with the slice name within the slice name range. The detecting includes at least one of interpreting a local slice name list of encoded data slices stored in local memory and verifying integrity of the retrieved encoded data slice.

The method continues at step 464 where the processing module performs a decentralized agreement protocol function on a slice name with regards to a plurality of storage pools to produce ranked scoring information. For example, the processing module performs the function utilizing location weights of each storage pool to produce a score for each storage pool.

The method continues at step 466 where the processing module identifies a storage pool associated with the encoded data slice based on the rank scoring information. For example, the processing module identifies a storage pool associated with a highest score of the ranked scoring information. When the identified storage pool is not substantially the same as a storage pool associated with the presence of the encoded data slice, the method continues at step 468 where the processing module indicates that the encoded data slice is the out-of-place encoded data slice. For example, the processing module issues slice status to a rebuilding module, where the slice status indicates the presence of the out-of-place encoded data slice.

When at least one storage pool of the plurality of storage pools indicates the out-of-place encoded data slice within a verification cycle, the method continues at step 470 where the processing module indicates that slice migration is not complete. For example, the processing module issues migration status indicating that the migration is still active. When each storage pool of the plurality of storage pools indicates an absence of the out-of-place encoded data slice within the verification cycle, the method continues at step 472 where the processing module indicates that the slice migration is complete. For example, the processing module issues migration status indicating that the migration has completed.

FIG. 43A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) that includes a legacy storage pool set 480, the network 24 of FIG. 1, a migration unit 484, and a new storage pool set 482. The legacy storage pool set 480 includes a plurality of storage generations (e.g., storage generation 0-G), where each storage generation includes a set of distributed storage and task (DST) execution (EX) units 1-n. The new storage pool set 482 includes a plurality of DST execution unit pools 1-P, where each DST execution unit pool includes a set of DST execution units 1-n. Each DST execution unit may be implemented utilizing the DST execution unit 36 of FIG. 1. Hereafter, a DST execution unit may be referred to as a storage unit and a DST execution unit pool and be referred to as a storage pool. The migration unit 484 may be implemented utilizing one or more of the DST processing unit 16 of FIG. 1, the DST integrity processing unit 20 of FIG. 1, and the distributed storage and task network (DSTN) managing unit 18 of FIG. 1. The DSN functions to modify a data access approach for stored data.

In an example of operation of the modifying of the data access approach, the migration unit 484 determines to convert the legacy storage pool set from a generation addressing approach to a non-generation addressing approach, where the legacy storage pool set includes two or more storage generations. The generation addressing approach includes utilizing a slice name for an encoded data slice, where each slice name includes a generation field that indicates which storage generation is utilized for the encoded data slice. The non-generation addressing approach includes utilizing the slice name to map to a unique storage pool in accordance with rank scoring information of a distributed agreement protocol function. The determining includes at least one of detecting an unfavorable storage efficiency of the legacy storage pool set and receiving a request.

Having determined to convert the legacy storage pool set, the migration unit converts a first storage generation of the legacy storage pool set into a first storage pool of the new storage pool set. The converting includes facilitating physically moving of storage units and transferring slices directly. For example, when physically moving the storage units, the migration unit facilitates (e.g., issues migration information 486 via the network 24) moving the DST execution units 1-n of the storage generation 0 to become the DST execution units 1-n of the DST execution unit pool 1 of the new storage pool set. As another example, when transferring slices directly, the migration unit instructs (e.g., issuing migration information via the network 24) the DST execution units of the storage generation 0 to send all encoded data slices to the storage units of the DST execution unit pool 1 for storage. The converting further includes establishing distributed agreement protocol function location weights of the first storage pool to correspond to slice names of the transferred encoded data slices from the first generation.

Having established the first storage pool of the new storage pool set, for each other storage generation of the two or more storage generations, the migration unit facilitates migration of encoded data slices from the other storage generation to one of the storage pools of the new storage pool set in accordance with the distributed agreement protocol function. For example, the migration unit performs the distributed agreement protocol function on a slice name of an encoded data slice for migration to produce ranked scoring information for the plurality of storage pools to identify the one storage pool (e.g., highest score) and facilitates migration of the encoded data slice from the storage generation to the identified storage pool (e.g., issues migration information that includes a migration command or obtains the encoded data slice and sends the encoded data slice to the identified storage pool for storage. The facilitating may further include provisioning (e.g., facilitating the activation of additional DST execution units) of the other storage pools of the storage pool set in accordance with a storage utilization level of the legacy storage.

FIG. 43B is a flowchart illustrating an example of modifying a data access approach for stored data. The method includes step 490 where a processing module (e.g., of a migration unit) determines to convert a legacy storage pool set from a generation addressing approach to a non-generation addressing approach. The determining includes at least one of detecting an unfavorable storage efficiency of the legacy storage pool set and receiving a request.

The method continues at step 492 where the processing module converts a first storage generation of the legacy storage pool set into a first storage pool of the new storage pool set. For example, the processing module establishes the distributed agreement protocol function location weights of the first storage pool to correspond to slice names of encoded data slices stored in the first storage generation and establishes the first generation as the first storage pool or transfers the encoded data slices of the first storage generation to a new storage pool that has been provisioned as the first storage pool of the new storage pool set.

For each other storage generation of the legacy storage pool set, the method continues at step 494 where the processing module facilitates migration of encoded data slices from the other storage generation to one storage pool of the new storage pool set in accordance with a distributed agreement protocol function. For example, the processing module performs the distributed agreement protocol function on a slice name of an encoded data slice for migration to produce ranked scoring information for the plurality of storage pools of the new storage pool set to identify the one storage pool (e.g., associated with a highest score) and facilitates migration of encoded data slice from the storage generation to the identified storage pool (e.g., issues migration information that includes a migration command or obtains encoded data slice and sends the encoded data slice to the identified storage pool for storage). The facilitating may further include the processing module provisioning of other storage pools of the new storage pool set in accordance with a storage utilization level of the legacy storage pool set.

FIGS. 44A-E are schematic block diagrams of another embodiment of a dispersed storage network (DSN) that includes a distributed storage and task (DST) execution (EX) unit set 500, the network 24 of FIG. 1, one or more DST processing units 1, 2, 3, etc., and a plurality of user devices A, B, C, etc. Each user device may be implemented utilizing the user device 14 of FIG. 1. The DST execution unit set 500 includes a set of DST execution units. Each DST execution unit may be implemented utilizing the DST execution unit 36 of FIG. 1. Hereafter, a DST execution unit may be interchangeably referred to as a storage unit and the DST execution unit set may be interchangeably referred to as one or more of a storage unit set, a set of storage units, and a centralized storage system. Each DST processing unit includes a combinatorial module 502 and the DST client module 34 of FIG. 1. The combinatorial module may be implemented utilizing at least one of the DST client module 34 of FIG. 1 and the processing module 84 of FIG. 3.

The DST execution unit set 500 includes a number of DST execution units in accordance with dispersal parameters of a dispersed storage error coding function, where the dispersal parameters includes a width n and a decode threshold number k. The decode threshold number is a minimum number of encoded data slices of a set of n encoded data slices that is required to recover a data segment, where the data segment is dispersed storage error encoded utilizing the dispersed storage error coding function in accordance with the dispersal parameters to produce the set of n encoded data slices. For example, a number of DST execution units of the DST execution unit set is n=11 when the width dispersal parameter is 11 and the decode threshold dispersal parameter is k=6 (e.g., requiring at least 6 encoded data slices to recover the data segment).

The DSN functions to select storage units of the storage unit set to access a unique combination of a decode threshold number of encoded data slices of a set of encoded data slices, where each user device A, B, C etc., is associated with one or more unique permutations (e.g., combinations) of the decode threshold number of encoded data slices of each set of encoded data slices. Generally, there are n choose k number of permutations of choosing the decode threshold number k of encoded data slices of the set of n encoded data slices. For example, there are 462 ways (e.g., 11 choose 6) to select the 6 decode threshold number of encoded data slices of the set of 11 encoded data slices. As an example of the unique association, the user device A is associated with a 10th (e.g., of the 462), unique combination that includes encoded data slices 4, 6, 7, 9, 10, 11; user device B is associated with a 163rd (e.g., of the 462) unique combination that includes encoded data slices 2, 3, 5, 7, 8, and 11; and user device C is associated with two unique emanations, where a 1st unique combination includes encoded data slices 5, 7, 8, 9, 10, and 11 and a 2nd unique combination includes encoded data slices 6, 7, 8, 9, 10, and 11.

FIG. 44A illustrates steps of an example of operation of the selecting of the storage units where the DST processing unit 1 receives, from a requesting device (e.g., user device A), a request to retrieve a unique copy of a data file from the centralized storage system, where the centralized storage system stores the data file as a plurality of sets of encoded data slices. Annie DST processing unit divides the data file into a plurality of data segments, where a data segment of the plurality of data segments is dispersed storage error encoded to produce a set of encoded data slices of the plurality of sets of encoded data slices, where a decode threshold number of encoded data slices of the set of encoded data slices is needed to recover the data segment, and where the plurality of sets of encoded data slices is stored in the set of storage units of the DSN.

Having received the request to retrieve the copy of the data file, the DST processing unit 1 determines a retrieval combination code from the request for the requesting device A. The determining includes a variety of approaches. A first approach includes extracting the retrieval combination code from the request. For example, the DST processing unit 1 extracts retrieval combination code 10 from the request. The second approach includes performing a lookup of the retrieval combination code based on identity of the requesting device. A third approach includes determining a group of combination request values from the request and based on the identity of the requesting device, selecting one of the combination request values from the group of combination request values (e.g., random, round-robin, based on storage unit status), and utilizing the selected combination request value as the retrieval combination code.

Having determined the retrieval combination code, the combinatorial module 502 of the DST processing unit 1 interprets the retrieval combination code to identify a sub-set of storage units of the set of storage units, where a number of storage units in the sub-set of storage units equals the decode threshold number. The interpreting the retrieval combination code includes converting the retrieval combination code into a binary number, where the binary number includes a number of bit positions and wherein the decode threshold number of the number of bit positions includes a one and a remaining number of the number of bit positions includes a zero. The DST client module 34 interprets the binary number to identify the sub-set of storage units, where the number of bit positions equals a number of storage units in the set of storage units and the interpreting the binary number further includes identifying the sub-set of storage units based on bit positions of the number of bit positions including a one.

As a specific example of interpreting the retrieval combination code to identify the sub-set of storage units, the combinatorial module 502 applies a combinatorial function to the retrieval combination code to produce a unique integer value of that is associated with the retrieval combination code. The requesting device may be associated with a plurality of unique integer values, where the plurality of unique integer values includes the unique integer value, where the plurality of unique integer values are associated with a plurality of retrieval combination codes associated with the requesting device, and where each of the plurality of unique integer values may be expressed as a binary number that includes n number of binary digits that correspond to storage units of the retrieval combination code. For example, the combinatorial module 502 of the DST processing unit 1 applies the combinatorial function to the retrieval combination code 10 to produce the integer value of 183.

Having produced the unique integer value, the DST client module 34 of the DST processing unit 1 converts the unique integer value into a corresponding binary number. For example, the DST client module 34 converts the integer value 183 into a binary string of 11 digits that includes [00010110111]. Having produced the binary number, the DST client module 34 identifies storage units of the storage unit set based on the binary number. For example, the DST client module 34 interprets system registry information to exclude storage units 1-3, include storage unit 4, exclude storage unit 5, include storage units 6-7, exclude storage unit 8, and include storage units 9-11 based on the binary number [00010110111].

Having identified the sub-set of storage units, the DST client module 34 sends read requests to the sub-set of storage units regarding the decode threshold number of encoded data slices. For example, the DST client module 34 of the DST processing unit 1 issues, via the network 24, read slice requests to the storage units 4, 6, 7, 9, 10, and 11.

FIG. 44B illustrates further steps of the example of operation of the selecting of the storage units where the DST client module 34 of the DST processing unit 1 receives, via the network 24, encoded data slices 4, 6, 7, 9, 10, and 11 as a permutation of the decode threshold number of encoded data slices unique to the user device A.

When the decode threshold number of encoded data slices is received, the DST client module 34 decodes the decode threshold number of encoded data slices to recover the data segment. For example, the DST client module 34 dispersed storage error decodes the encoded data slices 4, 6, 7, 9, 10, and 11 to produce at least a portion of data 1. Having recovered the data segment, the DST processing unit 1 provides the recovered data segment to the requesting device. For example, the DST client module 34 sends the at least a portion of the data 1 to the user device A.

FIG. 44C illustrates further steps of the example of operation of the selecting of the storage units where the DST processing unit 2 receives, from the user device B, a request to retrieve another unique copy of the data file 1 from the centralized storage system. Having received the request, the DST processing unit 2 determines a retrieval combination code from the request for the requesting device B. For example, the combinatorial module 502 of the DST processing unit 2 identifies the retrieval combination code of 163 by extracting the retrieval combination code 163 from the request. Having determined the retrieval combination code, the DST processing unit 2 interprets the retrieval combination code to identify a sub-set of storage units of the set of storage units for data retrieval on behalf of the user device B. For example, the combinatorial module 502 of the DST processing unit 2 applies the combinatorial function to the retrieval combination code 163 to produce a unique integer value of 857 that is associated with the retrieval combination code 163. Having produced the unique integer value, the DST client module 34 of the DST processing unit 2 converts the unique integer value into a binary number and interprets the binary number to identify the sub-set of storage units. For example, the DST client module 34 converts the unique integer value of 857 into a binary number of [01101011001] corresponding to storage units 2, 3, 5, 7, 8, and 11. Having identified the sub-set of storage units, the DST client module 34 of the DST processing unit 2 issues, via the network 24, read slice requests to the sub-set of storage units 2, 3, 5, 7, 8, and 11 regarding the decode threshold number of encoded data slices (e.g., encoded data slices 2, 3, 5, 7, 8, and 11).

The DST processing unit 3 receives, from the user device C, a request to retrieve yet another unique copy of the data file 1 from the centralized storage system. Having received the request, the DST processing unit 3 determines a retrieval combination code from the request for the requesting device C. For example, the combinatorial module 502 of the DST processing unit 2 selects retrieval combination code 2 of identified retrieval combination codes of 2 and 1 by performing a lookup based on identity of the user device C. Having determined the retrieval combination code, the DST processing unit 3 interprets the retrieval combination code to identify a sub-set of storage units of the set of storage units for data retrieval on behalf of the user device C. For example, the combinatorial module 502 of the DST processing unit 3 applies the combinatorial function to the retrieval combination code 2 to produce a unique integer value of 95 that is associated with the retrieval combination code 2. Having produced the unique integer value, the DST client module 34 of the DST processing unit 3 converts the unique integer value into a binary number and interprets the binary number to identify the sub-set of storage units. For example, the DST client module 34 converts the unique integer value of 95 into a binary number of [00001011111] corresponding to storage units 6, 7, 8, 9, 10, and 11. Having identified the sub-set of storage units, the DST client module 34 of the DST processing unit 3 issues, via the network 24, read slice requests to the sub-set of storage units 6, 7, 8, 9, 10, and 11 regarding the decode threshold number of encoded data slices (e.g., encoded data slices 6, 7, 8, 9, 10, and 11.

FIG. 44D illustrates further steps of the example of operation of the selecting of the storage units where the DST client module 34 of the DST processing unit 2 receives, via the network 24, encoded data slices 2, 3, 5, 7, 8, and 11 from the storage units 2, 3, 5, 7, 8, and 11. When the decode threshold number of encoded data slices is received, the DST client module 34 of the DST processing unit 2 decodes the decode threshold number of encoded data slices 2, 3, 5, 7, 8, and 11 to recover the data segment and sends at least the recovered data segment of data 1 to the requesting device B.

The DST client module 34 of the DST processing unit 3 receives, via the network 24, encoded data slices 7, 8, 9, 10, and 11 when encoded data slice 6 is unavailable from the DST execution unit 6. When the decode threshold number of encoded data slices is not received, the DST processing unit 3 identifies storage units of the sub-set of storage units for which an encoded data slice of the decode threshold number of encoded data slices was successfully received. For example, the DST client module 34 of the DST processing unit 3 identifies encoded data slices 7, 8, 9, 10, and 11 as successfully received encoded data slices. Having identified the successfully received encoded data slices, the DST processing unit 3 generates a partial retrieval combination code based on the identity of the storage units of the sub-set of storage units for which the encoded data slice was successfully received. For example, the DST client module 34 identifies the partial retrieval combination code of 2 or when all that one of the encoded data slices associated with the retrieval, nation code of 2 have been successfully received. Having generated the partial retrieval, nation code the DST processing unit 3 determines an alternate retrieval combination code that approximates the partial retrieval combination code and conforms to the retrieval combination code of the requesting device. For example, the DST processing unit 3 determines retrieval combination code 1 as the alternate retrieval combination code when the retrieval combination code 1 corresponds to a binary number that excludes a storage unit associated with a retrieval failure (e.g., encoded data slice 6 was not received from storage unit 6) and the retrieval combination code 1 is associated with the user device C.

Having identified the alternate retrieval combination code, the DST processing unit 3 interprets the alternate retrieval combination code to identify another storage unit of the set of storage units to retrieve another encoded data slice of the set of encoded data slices. For example, the combinatorial module 502 applies the combinatorial function to the retrieval combination code 1 to produce a unique integer value of 63 that is associated with the retrieval combination code 1. Having produced the unique integer value, the DST client module 34 of the DST processing unit 3 converts the unique integer value into a binary number and interprets the binary number to identify the sub-set of storage units to identify the other storage unit. For example, the DST client module 34 converts the unique integer value of 63 into a binary number of [00000111111] corresponding to storage units 5, 7, 8, 9, 10, and 11. Having identified the sub-set of storage units, the DST client module 34 of the DST processing unit 3 identifies storage unit 6 as the other storage unit when the remaining identified storage units are substantially the same as storage units of the sub-set of storage units associated with the previous read cycle where the read failed for one of the storage units (e.g., storage unit 6). Having identified the other storage unit, the DST processing unit 3 sends a retrieval request to the other storage unit regarding the other encoded data slice. For an example, the DST client module 34 of the DST processing unit 3 issues, via the network 24, a read slice request to the other storage unit 5 regarding the other encoded data slice 5.

FIG. 44E illustrates further steps of the example of operation of the selecting of the storage units where the DST client module 34 of the DST processing unit 3 receives, via the network 24, encoded data slice 5 from the storage unit 5. When the decode threshold number of encoded data slices is received, the DST client module 34 of the DST processing unit 3 decodes the decode threshold number of encoded data slices 5, 7, 8, 9, 10, and 11 to recover the data segment and sends at least the recovered data segment of data 1 to the requesting device C

FIG. 44F is a flowchart illustrating an example of selecting storage units. In particular, a method is presented for use in conjunction with one or more functions and features described in conjunction with FIGS. 1-39, 44A-E, and also FIG. 44F. The method begins at step 510 where a processing module of a computing device of one or more computing devices of a dispersed storage network (DSN) receives, from a requesting device, a request to retrieve a unique copy of a data file from a centralized storage system, where the centralized storage system stores the data file as a plurality of sets of encoded data slices, where the data file is divided into a plurality of data segments, where a data segment of the plurality of data segments is dispersed storage error encoded to produce a set of encoded data slices of the plurality of sets of encoded data slices, where a decode threshold number of encoded data slices of the set of encoded data slices is needed to recover the data segment, and where the plurality of sets of encoded data slices is stored in a set of storage units of the DSN.

The method continues at step 512 where the processing module determines a retrieval combination code from the request for the requesting device. The determining of the retrieval combination code includes determining a group of combination request values from the request and based on identity of the requesting device, selecting one of the combination request values from the group of combination request values, and utilizing the selected combination request value as the retrieval combination code.

The method continues at step 514 where the processing module interprets the retrieval combination code to identify a sub-set of storage units of the set of storage units, where a number of storage units in the sub-set of storage units equals the decode threshold number. The interpreting the retrieval combination code includes converting the retrieval combination code into a binary number, where the binary number includes a number of bit positions and where the decode threshold number of the number of bit positions includes a one and a remaining number of the number of bit positions includes a zero, and interpreting the binary number to identify the sub-set of storage units. The number of bit positions equals a number of storage units in the set of storage units and the interpreting the binary number further includes identifying the sub-set of storage units based on bit positions of the number of bit positions including a one (e.g., a first storage unit corresponding to a first bit position, etc.).

The method continues at step 516 where the processing module sends read requests (e.g., a decode threshold number of read slice requests) to the sub-set of storage units regarding the decode threshold number of encoded data slices. The method continues at step 518 where the processing module determines whether the decode threshold number of encoded data slices have been received within a receiving time frame. The method branches to step 530 when the decode threshold number of encoded data slices is received. The method continues to step 520 when the decode threshold number of encoded data slices is not received.

When the decode threshold number of encoded data slices is not received, the method continues at step 520 where the processing module identifies storage units of the sub-set of storage units for which an encoded data slice of the decode threshold number of encoded data slices was successfully received. The method continues at step 522 where the processing module generates a partial retrieval combination code based on the identity of the storage units of the sub-set of storage units for which the encoded data slice was successfully received.

The method continues at step 524 where the processing module determines an alternate retrieval combination code that approximates the partial retrieval combination code and conforms to the retrieval combination code of the requesting device (e.g., associated with the group of retrieval combination codes associated with the requesting device). The method continues at step 526 where the processing module interprets the alternate retrieval combination code to identify another storage unit of the set of storage units to retrieve another encoded data slice of the set of encoded data slices. The method continues at step 528 where the processing module sends a retrieval request to the other storage unit regarding the other encoded data slice. The method continues to step 530.

When the decode threshold number of encoded data slices is received, the method continues at step 530 where the processing module decodes the decode threshold number of encoded data slices to recover the data segment. The method continues at step 532 where the processing module provides the recovered data segment to the requesting device. For example, the processing module decodes each decode threshold number of encoded data slices of each of the plurality of sets of encoded data slices to reproduce the plurality of data segments, aggregates the plurality of data segments to reproduce the data file, and sends the data file to the requesting device.

The method described above in conjunction with the processing module can alternatively be performed by other modules of the dispersed storage network or by other devices. In addition, at least one memory section (e.g., a non-transitory computer readable storage medium) that stores operational instructions can, when executed by one or more processing modules of one or more computing devices of a group of computing devices of the dispersed storage network (DSN), cause the one or more computing devices to perform any or all of the method steps described above, where each computing device includes one or more of an interface, memory, and the processing module.

FIG. 45A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) that includes a migration agent module 580, the network 24 of FIG. 1, and at least two distributed storage and task (DST) execution (EX) unit pools 1-2, etc. The migration agent module 580 includes a decentralized agreement module 582 and the DST client module 34 of FIG. 1. The decentralized agreement module 582 may be implemented utilizing the decentralized agreement module 350 of FIG. 40A. Each DST execution unit pool includes a set of DST execution units 1-n. Each DST execution unit may be implemented utilizing the DST execution unit 36 of FIG. 1. Hereafter, each DST execution unit may be referred to interchangeably as a storage unit and each DST execution unit pool may be referred to interchangeably as a storage unit pool. The DSN functions to pace migration of encoded data slices from a storage pool to another storage pool.

In an example of operation of the pacing of the migration of the encoded data slices, the migration agent module 580 determines to migrate the encoded data slices from the storage pool 1 to the other storage pool 2. The determining includes at least one of detecting storage unit retirement, detecting a storage unit replacement, detecting new storage resources, detecting new location weights of a distributed agreement protocol function associated with storage units and/or with one or more storage pools, interpreting a request, and interpreting a slice migration schedule.

Having determined to migrate encoded data slices, the migration agent module 580 identifies storage resources associated with the encoded data slices for migration. The identifying includes at least one of obtaining slice names of the encoded data slices for migration, performing a lookup of storage resource identifiers associated with the obtained slice names to identify storage locations for the encoded data slices for migration, and performing a distributed agreement protocol function on the slice names utilizing location weights for associated storage resources to identify the destination locations for the encoded data slices for migration. For example, the DST client module 34 issues a ranked scoring information request 584 to the decentralized agreement module 582, where the request includes a slice name for encoded data slice of the first storage pool for migration, receives ranked scoring information 586 from the decentralized agreement module 582, and identifies the second storage pool as the destination resource based on a highest score of the ranked scoring information 586.

Having identified the storage resources, the migration agent module 580 obtains performance information 588 associated with the identified storage resources. The performance information 588 includes one or more of slice access latency level (e.g., retrieval delay, storage time frame), slice access capacity level (e.g., bandwidth), a network resource availability level, and a storage resource availability level. The obtaining includes at least one of interpreting a query response, interpreting an error message, receiving the performance information from the identified storage resources, initiating a test, and interpreting a test result. For example, the DST client module 34 receives, via the network 24, the performance information 588 from the DST execution units of the DST execution unit pools 1 and 2.

Having obtained the performance information 588, the migration agent module 580 generates a migration schedule 590 for the encoded data slices for migration based on the performance information 588. The migration schedule 590 includes one or more of slice names of the slices for migration, a desired time of migration completion, a migration pacing factor (e.g., a target migration rate, a migration aggressiveness level), an expected slice access loading level profile (e.g., a user device access rate, the rebuilding rate), and a maximum impact level (e.g., a degradation of slice access performance, a lowest threshold level of slice access performance). The generating includes one or more of identifying a portion of slice names of the encoded data slices for migration and identifying a time frame of the migration for the identified portion based on at least a portion of the performance information (e.g., generate a migration pacing factor based on a desired time frame of completion of the migration and the performance information).

Having generated the migration schedule 590, the migration agent module sends the migration schedule 590 to the identified storage resources to facilitate the migration of the encoded data slices for migration. For example, the DST client module 34 sends, via the network 24, the migration schedule 590 to the DST execution units of the first and second storage pools. Having received the migration schedule 590, the identified storage resources perform the migration. For example, the storage units of the first storage pool send, via the network 24, migration slices 592 to the second storage pool for storage in accordance with the migration schedule.

Prior to completion of the migration, the migration agent module 580 obtains updated performance information 588. Having obtained the updated performance information 588, the migration agent module 580 updates the migration schedule 590 to produce an updated migration schedule when the updated performance information compares unfavorably to a desired performance information level. The updating includes one or more of detecting the unfavorable conditions (e.g., storage resource availability level is less than a desired minimum storage resource availability level, slice access performance level has degraded beyond a degradation threshold level, etc.; and adjusting the migration pacing factor to produce the updated migration schedule. When updating the performance information, the migration agent module sends, via the network 24, the updated migration schedule to the identified storage resources.

FIG. 45B is a flowchart illustrating an example of pacing migration of encoded data slices. The method includes step 600 where a processing module (e.g., of a migration agent module) determines to facilitate migration of encoded data slices from one or more storage resources to one or more other storage resources. The determining includes one or more of detecting a storage unit retirement and/or replacement, detecting provisioning of a new storage unit, detecting new location weights, receiving a request, identifying source storage resources by performing a lookup, and identify destination storage resources by performing a distributed agreement protocol function on the slice names.

The method continues at step 602 where the processing module obtains performance information associated with the storage resources of the migration. The obtaining includes at least one of receiving the performance information from the storage resources, interpreting a test result, and interpreting a query response.

The method continues at step 604 where the processing module generates a migration schedule for the encoded data slices for migration based on the performance information. For example, the processing module assigns a migration pacing factor to a portion of the slices for migration based on a time frame of migration and performance information.

The method continues at step 606 where the processing module sends the migration schedule to the storage resources of the migration. For example, the processing module transmits the migration schedule to at least some storage resources of the storage resources of the migration, where the storage resources utilize the migration schedule when performing one or more steps of the migration of the encoded data slices.

The method continues at step 608 where the processing module obtains updated performance information while the slice migration is active. For example, the processing module issues a performance information request and receives the updated performance information.

The method continues at step 610 where the processing module updates the migration schedule when the updated performance information compares unfavorably to a desired performance level. For example, the processing module detects unfavorable execution of the migration of the encoded data slices (e.g., a slice access performance level has degraded beyond a degradation threshold level, etc.) and updates the migration pacing factor. The method continues at step 612 where the processing module sends the updated migration scheduled to the storage resources of the migration. For example, the processing module transmits the updated migration schedule to at least some storage resources of the storage resources of the migration, where the storage resources utilize the updated migration schedule when performing further steps of the migration of the encoded data slices (e.g., slowing down sending of the further slices of the migration).

FIG. 46A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) that includes the distributed storage and task (DST) processing unit 16 of FIG. 1, the distributed storage and task network (DSTN) managing unit 18 of FIG. 1, the network 24 of FIG. 1, and a DST execution (EX) unit set 620. The DST execution unit set 620 includes a set of DST execution units 1-n. Each DST execution unit includes the processing module 84 of FIG. 3 and a plurality of memories 1-M. Each memory may be implemented utilizing the memory 88 of FIG. 3. Each DST execution unit may be implemented utilizing the DST execution unit 36 of FIG. 1. Hereafter, each DST execution unit may be interchangeably referred to as a storage unit and the DST execution unit set may be interchangeably referred to as a storage unit set. The DSN functions to handle a memory device error condition.

In an example of operation of the handling of the memory device error condition, a processing module 84 of a storage unit detects a memory error associated with a memory device of the storage unit while the storage unit is generally servicing slice access messages 624 (e.g., write slice request, read slice requests, etc.) from the DST processing unit 16. The detecting includes one or more of interpreting an error message, interpreting a test result, detecting a timing issue, detecting a data error, detecting a naming error, detecting a data age error, etc. For example, the processing module 84 of the DST execution unit 1 detects a memory error associated with the memory device 2.

Having detected the memory error, the storage unit identifies an error descriptor code based on the detected memory error. See the error code list below for further details on the error descriptor codes. The identifying includes at least one of performing a lookup (e.g., of the error code list), interpreting a query response, interpreting system registry information, and receiving the error descriptor code. For example, the processing module 84 of the DST execution unit 1 detects a first error code type associated with storage of slices 1-2 by a memory 2.

Having identified the error descriptor code, the storage unit determines whether to perform and intermediate action based on the error descriptor code. For example, the processing module 84 performs a lookup in an intermediate action table using the error descriptor code to identify whether the intermediate action is associated with the error descriptor code.

When not performing the intermediate action, the storage unit issues a memory status information 622 to the DSTN managing unit 18, where the memory status information includes one or more of an identifier of the memory device, an identifier of the storage unit, the error descriptor code, and a failed status indicator. The issuing includes generating the memory status information and sending, via the network 24, the memory status information 622 to at least the DSTN managing unit 18. The generating may further include changing the memory status information to indicate unavailability based on the error descriptor (e.g., immediately failed memory device and quarantine from further utilization for a particular error descriptor).

When performing the intermediate action, the storage unit performs the intermediate action to produce an action result. The performing includes one or more of executing a lookup in the intermediate action table using the error descriptor code to identify the intermediate action and executing the identify the intermediate action to produce action result. The intermediate action includes one or more of performing a power cycling of the memory device, facilitating resumption of normal operations, resetting the storage unit operations, resuming the storage unit operations, and initiating a memory test. For example, the processing module 84 initiates the memory test of the memory device 2 and produces test results as the action result.

Having performed the intermediate action, the storage unit determines whether the memory device is to remain in service based on one or more of action result and the error descriptor code. For example, the storage unit indicates to remain in service when the action result compares favorably to a desired action result based on the error descriptor code (e.g., processing subsequent access messages properly).

When the memory device is not to remain in service, the storage unit issues further memory status information to the DSTN managing unit 18 to indicate the failed status indicator. The issuing includes generating the memory status information to indicate the failed status and sending, via the network 24, the further memory status information to the DSTN managing unit 18.

Error Code List:

Memory Devices can fail or otherwise manifest error condition in numerous ways, and the best corrective actions to take may depend on the reason/type of error condition that occurred. To this end, numerous error condition cases are identified as well as a method for potential recovery or actions to take for each error condition. The error conditions are defined numerically as follows:

-   -   1. SMART (Self-Monitoring, Analysis, and Reporting Technology)         failure: This reason indicates that the memory device has failed         a manufacturer defined SMART threshold. In general, a memory         device that fails a manufacturer defined SMART threshold should         be replaced immediately. However, some can fail these thresholds         and subsequently clear that failure condition (e.g., flying         height of heads, health status of the drive, generally measured         parameters compared against predefined thresholds).     -   2. SMART command failure: This reason indicates that the SMART         command failed to execute. This is usually indicative of a         problem accessing the memory device and is strongly correlated         with memory device failures. However, with the some memory         devices there are situations where this failure mode is quite         common and a power cycle of the memory device may clear the         issue. Power cycling the memory device requires a complete power         off of the storage unit or that the memory device in question be         physically removed and reinserted into the storage unit. After a         power cycle, the memory device can be resumed and, if it is         quarantined again, it should be replaced.     -   3. User Action: This reason indicates that a user manually         quarantined a memory device for testing purposes. This reason         should never be seen in production. If it is, a review of the         command history for the storage unit for both the root and local         admin account should reveal that a user manually quarantined the         memory device. The quarantined memory device should be resumed         via the storage command or from the manager UI.     -   4. Too many errors on memory device—This reason indicates that         the application exceeded a threshold number of input-output         (I/O) errors during a 1 minute interval while writing to the         affected memory device. A logging messages file should be         reviewed to confirm the health of the memory device. If there         are a significant number of errors reported for the memory         device in question and in particular if there are media errors         reported for the memory device, it probably needs to be         replaced. However, the errors on the memory device may be very         localized and a resume of the memory device may prove         successful.     -   5. Too many timeouts on memory device—This reason indicates that         the application exceeded a threshold number of IO timeouts         during a 5 minute interval. Timeouts on the memory device may be         caused by problems with the memory device or by events occurring         at the controller level such as resets. This reason may also         arise as a result of IO errors on a neighboring memory device.         The recommended action to take for a memory device that has been         quarantined for IO timeouts is to resume the memory device after         reviewing the logging messages and confirming that there do not         appear to be significant errors reported for the memory device.         If it is quarantined again within a few days, it should be         replaced.     -   6. Invalid Internal Structure (identity is not accessible)—This         is one of several reasons that can be reported as an invalid         internal structure issue. This specific reason deals with an         inaccessible memory device identity file which may arise if a         memory device has been incorrectly mounted read only. This         condition is expected to occur very rarely and, if it does         arise, the memory device should be proactively failed to migrate         the namespace and subsequently replaced on the next scheduled         maintenance cycle.     -   7. Invalid Internal Structure (insufficient permissions)—This         reason refers to a condition where the application cannot create         metadata artifacts on the memory device. This condition is         expected to occur very rarely and, if it does arise, the memory         device should be proactively failed to migrate the namespace and         subsequently replaced on the next scheduled maintenance cycle.     -   8. Invalid Internal Structure (error saving metadata)—This         reason refers to a condition where the application cannot save         metadata to the memory device. This condition is expected to         occur very rarely and, if it does arise, the memory device         should be proactively failed to migrate the namespace and         subsequently replaced on the next scheduled maintenance cycle.     -   9. Invalid Internal Structure (error creating metadata)—This         reason deals with a similar situation to reason 7 but at the         time of metadata creation. This condition is expected to occur         very rarely and, if it does arise, the memory device should be         proactively failed to migrate the namespace and subsequently         replaced on the next scheduled maintenance cycle.     -   10. Corrupted slice name—This reason indicates that the         application encountered a slice name that does not correspond to         expected formats. A file system check followed by a resume         operation on the memory device may clear the condition but if         the memory device continues to be quarantined for this reason,         it should be replaced.     -   11. Invalid Internal Structure (missing or inaccessible data         structure)—This reason indicates that the metadata directories         on the memory device are unreadable and/or unwritable. A file         system check followed by a resume operation on the memory device         may clear this condition and, if not, the case should be         escalated to support for further investigation.     -   12. Invalid Internal Structure (corrupted data structure)—This         reason indicates that a data structure such as a directory was         found to be corrupted. For example, we found a file where we         expected a directory or vice-versa. A file system check followed         by a resume operation on the memory device may clear the         condition but if the memory device continues to be quarantined         for this reason, it should be replaced.     -   13. Invalid Internal Structure (10 error reading data from         storage mapping file)—This reason indicates a corruption of the         data file that defines the storage mapping on memory device. If         this situation arises, the memory device should be proactively         failed to migrate the namespace and subsequently replaced on the         next scheduled maintenance cycle. However this is indicative of         a software defect and the case should also be escalated to         support for investigation and recovery of the mapping file.     -   14. Data upgrade failed—This reason may be generated after         upgrade if an error occurs when an attempt to convert metadata         from old version to the new format compatible with new release     -   15. Data version too old—This reason is generated when the data         or metadata version on the memory device is more than one         versioned release behind

FIG. 46B is a flowchart illustrating an example of handling a memory device error condition. The method includes step 630 where a processing module (e.g., of a storage unit) detects a memory error associated with a memory device of a storage unit. The detecting includes one or more of interpreting an error message, interpreting a test result, detecting a timing issue, detecting a data error, detecting a naming error, and detecting a data age error. The method continues at step 632 where the processing module identifies an error descriptor code based on the detected memory error. The identifying includes at least one of interpreting system registry information, interpreting a query response, performing a lookup, and receiving the error descriptor code.

The method continues at step 634 where the processing module determines whether to perform an intermediate action based on the error descriptor code. For example, the processing module uses the error descriptor code 2 performing a lookup in an intermediate action table. When the intermediate action is to be performed, the method branches to step 638. When the intermediate action is not to be performed, the method continues to step 636. When not performing the intermediate action, the method continues at step 636 where the processing module issues status information to a managing unit. The issuing includes generating the status information to indicate one or more of an identifier of the failed memory device, the error descriptor code, and an identifier of the storage unit.

When performing the intermediate action, the method continues at step 638 where the processing module performs the intermediate action to produce an action result. The performing includes one or more of identifying the intermediate action in the intermediate action table, executing the intermediate action, and measuring an outcome to produce the action result.

The method continues at step 640 where the processing module determines whether the memory devices to remain in service based on one or more of the action result and the error descriptor code. For example, the processing module indicates that the memory device is not to remain in service when the action result compares unfavorably to a desired action result based on the error descriptor code. When the memory device is not to remain in service, the method continues at step 642 where the processing module issues further status information to the managing unit. For example, the processing module generates the further status information to indicate one or more of failure the memory device, the identifier of the memory device, and the identifier of the storage unit.

FIG. 47A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) that includes the distributed storage and task (DST) client module 34 of FIG. 1, the network 24 of FIG. 1, and a storage set 650. The DST client module 34 includes the inbound DST processing 82 of FIG. 3. The storage set includes a set of DST execution units, where some of the DST execution units may, from time to time, be in a power savings mode where at least a portion of the DST execution unit is powered down to save energy. Each DST execution unit may be implemented utilizing the DST execution unit 36 of FIG. 1. Hereafter, each DST execution unit may be interchangeably referred to as a storage unit and the storage set may be interchangeably referred to as a storage unit set.

The storage set may include a number of DST execution units in accordance with dispersal parameters of a dispersed storage error coding function, where the dispersal parameters includes a width n, a read threshold number, and a decode threshold number k. The decode threshold number is a minimum number of encoded data slices of a set of n encoded data slices that is required to recover a data segment, where the data segment is dispersed storage error encoded utilizing the dispersed storage error coding function in accordance with the dispersal parameters to produce the set of n encoded data slices. For example, a number of DST execution units of the DST execution unit set is n=8 when the width dispersal parameter is 8 and the decode threshold dispersal parameter is k=5 (e.g., requiring at least 5 encoded data slices to recover the data segment). The read threshold number includes a number of desired encoded data slices of the set of encoded data slices for recovery to provide the decode threshold number of encoded data slices. The DSN functions to recover data stored in the storage unit set, where data is dispersed storage error encoded to produce at least one set of encoded data slices that is stored in the set of DST execution units (e.g., a data segment is encoded to produce a set of encoded data slices 1-8 that are stored in the DST execution units 1-8).

In an example of operation of the recovering of the stored data, the inbound DST processing 82 receives a data request 652 to recover the data segment. Having received the data request 652, the inbound DST processing 82 issues a read threshold number of read slice requests to storage units of the storage set. The issuing includes one or more of generating the read slice requests; selecting the storage units based on one or more of a predetermination, storage unit performance levels, a storage unit availability levels, and a random selection; and sending, via the network 24, the read slice requests to the selected storage units. For example, the inbound DST processing 82 selects DST execution units 1-6 and sends, via the network 24, read slice requests 1-6 to the DST execution units 1-6.

Having sent the read threshold number of read slice requests, the inbound DST processing 82 receives read slice responses from at least some of the storage units within a response timeframe. For example, the inbound DST processing 82 receives read slice responses that includes encoded data slices 1, 2, 4, and 5 (e.g., no response from DST execution unit 3), and receives another read slice response that includes an error response 6 from the DST execution unit 6.

When the received read slice responses includes less than the decode threshold number of encoded data slices of the set of encoded data slices, the inbound DST processing 82 generates at least one forced read slice request for at least one other encoded data slice. The generating includes determining a number of forced read slice request based on a number of received encoded data slices and the decode threshold number. For example, the inbound DST processing 82 determines to generate one forced read slice request when receiving four encoded data slices and the decode threshold number is five.

Having generated the at least one forced read slice request, the inbound DST processing 82 sends, via the network 24, the at least one forced read slice request to at least one storage unit of the set of storage units. The sending includes selecting a storage unit and transmitting a corresponding forced read request to the selected storage unit. For example, the inbound DST processing 82 selects a storage unit corresponding to a received error response indicating unavailability of a corresponding encoded data slice without powering up a portion of the storage unit. For instance, the inbound DST processing 82 selects DST execution unit 6 when the error response 6 indicates that the encoded data slice 6 is unavailable without powering up a portion of the DST execution unit 6 and transmits, via the network 24, the forced read slice request 6 to the DST execution unit 6. As another example of the selecting of the storage unit, the inbound DST processing 82 selects a remaining storage unit of the set of storage units (e.g., selects DST execution unit 7).

The inbound DST processing 82 receives a further read slice response in response to the at least one forced read slice request from the storage set. For example, the DST execution unit 6 transitions from a power savings mode to at least a partially active power mode to retrieve the encoded data slice 6 from a corresponding memory device, and sends, via the network 24, the encoded data slice 6 to the inbound DST processing 82. When receiving the decode threshold number of encoded data slices, the inbound DST processing 82 dispersed storage error decodes the received decode threshold number of encoded data slices to reproduce a data segment of the data to produce recovered data 654.

FIG. 47B is a flowchart illustrating an example of recovering data stored in a dispersed storage network (DSN). The method includes step 660 where a processing module (e.g., of a distributed storage and task (DST) client module) receives a data request. The method continues at step 662 where the processing module issues a read threshold number of read slice requests to storage units of a set of storage units. For example, the processing module generates the read slice requests, selects the storage units (e.g., based on one or more of a predetermination, a performance level, a random selection, a power savings mode, and an availability level), and sends the read slice requests to the selected storage units.

The method continues at step 664 where the processing module receives read slice responses from at least some of the storage units within a response timeframe. When the received read slice responses includes less than a decode threshold number of encoded data slices of a set of encoded data slices, the method continues at step 666 where the processing module generates at least one forced read slice request for an encoded data slice other than the received encoded data slices. The generating includes determining a number of forced read slice request to generate based on a difference between the decode threshold number and a number of received encoded data slices.

The method continues at step 668 where the processing module sends the at least one forced read slice request to at least one storage unit. For example, the processing module sends the at least one forced read slice request to a storage unit that corresponds to an error response indicating unavailability of an associated encoded data slice unless powered up. As another example, the processing module sends the at least one forced read slice request to another storage unit outside of the selected storage units of the read threshold number of read slice requests. When receiving the decode threshold number of encoded data slices, the method continues at step 670 where the processing module decodes the received decode threshold number of encoded data slices to reproduce a data segment of recovered data.

FIGS. 48A-B are a schematic block diagram of another embodiment of a dispersed storage network (DSN) that includes a distributed storage and task (DST) execution (EX) unit set 680, the network 24 of FIG. 1, and the DST processing unit 16 of FIG. 1. The DST execution unit set 680 includes a set of DST execution units, where at least some of the DST execution units may, from time to time, be in a power savings mode where at least a portion of the DST execution unit is temporarily powered down to save energy. Each DST execution unit may be implemented utilizing the DST execution unit 36 of FIG. 1. Hereafter, each DST execution unit may be interchangeably referred to as a storage unit and the DST execution unit set may be interchangeably referred to as a storage unit set.

The DST execution unit set 680 may include a number of DST execution units in accordance with dispersal parameters of a dispersed storage error coding function, where the dispersal parameters includes a width n, a write threshold number, and a decode threshold number k. The decode threshold number is a minimum number of encoded data slices of a set of n encoded data slices that is required to recover a data segment, where the data segment is dispersed storage error encoded utilizing the dispersed storage error coding function in accordance with the dispersal parameters to produce the set of n encoded data slices. For example, a number of DST execution units of the DST execution unit set is n=11 when the width dispersal parameter is 11 and the decode threshold dispersal parameter is k=6 (e.g., requiring at least 6 encoded data slices to recover the data segment). The write threshold number includes a minimum number of encoded data slices of the set of encoded data slices to be stored in the set of DST execution units.

The DSN functions to maintain encoded data slice storage (e.g., storing and rebuilding) with regards to power utilization of the DST execution units, where data is dispersed storage error encoded to produce at least one set of encoded data slices, and where the read threshold number of encoded data slices of the set of encoded data slices is stored in the set of DST execution units (e.g., a data segment is encoded to produce a set of encoded data slices 1-11 such that that at least a decode data slices are stored in the DST execution units 1-11).

FIG. 48A illustrates steps of an example of operation of the maintaining of the encoded data slice storage where the DST processing unit 16 selects a first subset of storage units of the storage unit set for temporary deactivation (e.g., power savings mode, based on the read threshold number. The selecting includes at least one of utilizing a random selection approach, selecting in accordance with a predetermination, utilizing a request, interpreting a schedule, utilizing a round robin approach, and interpreting storage unit information 682 to identify power usage, etc. For example, the DST processing unit 16 selects the number of storage units for deactivation according to a difference between the width n and the read threshold number (e.g., 11−8=3). For instance, the DST processing unit 16 selects the first subset of storage units to include the DST execution units 9-11 for deactivation.

Having selected the first subset of storage units, the DST processing unit 16 issues a request message to the first subset of storage units to temporarily deactivate the selected for subset of storage units as deactivated storage units. For example, the DST processing unit 16 issues, via the network 24, storage unit information, that includes a de-activation request, to DST execution units 9-11. While the first subset of storage units are deactivated, the DST processing unit 16 maintains the read threshold number of encoded data slices 684 for each stored set of encoded data slices. For example, the DST processing unit 16 generates encoded data slices 1-8 and sends, via the network 24, the encoded data slices 1-8 to the DST execution units 1-8 for storage when receiving new data for storage and the DST execution units 9-11 are deactivated. As another example, the DST processing unit 16 rebuilds an encoded data slice of encoded data slices 1-8 corresponding to a storage error to further maintain the number of encoded data slices at the read threshold number of 8.

FIG. 48B illustrates further steps of the example of operation of the maintaining of the encoded data slice storage where, as new data is stored to the remaining storage units (e.g., DST execution units 1-8), the DST processing unit 16 detects a storage imbalance between the remaining storage units and the deactivated storage units (e.g., DST execution units 9-11). The detecting includes at least one of determining that a difference between storage utilization of the remaining storage units and storage utilization of the deactivated storage units is greater than a storage utilization difference threshold level, detecting that a storage timeframe is expired, and interpreting an error message.

Having detected the storage imbalance, the DST processing unit 16 selects a second subset of storage units for temporary deactivation. For example, the DST processing unit 16 selects DST execution units 6-8 for the temporary deactivation. Having selected the second subset of storage units, the DST processing unit 16 issues another request message to the deactivated storage units to reactivate the deactivated storage units as reactivated storage units. Example, the DST processing unit 16 generates further storage unit information that includes the request to reactivate and sends, via the network 24, the further storage unit information to the DST execution units 9-11 to reactivate the DST execution units 9-11.

Having issued the request message to reactivate the deactivated storage units, the DST processing unit 16 facilitates storage rebalancing by storing encoded data slices 684 (e.g., transferred slices, newly stored encoded data slices while the first subset of storage units was temporarily deactivated) in the reactivated storage units. For example, the DST processing unit 16 facilitates copying of encoded data slices 6-8 from the DST execution units 6-8 to the DST execution units 9-11. As another example, the DST processing unit 16 rebuilds missing encoded data slices (e.g., encoded data slices 9-11) associated with the reactivated storage units. As yet another example, the DST processing unit 16 facilitates storing new encoded data slices 9-11 in the DST execution units 9-11. Having facilitated the storage rebalancing, the DST processing unit 16 issues yet another request message to the second subset of storage units to temporarily deactivate the second set of storage units. For example, the DST processing unit 16 sends, via the network 24 still further storage unit information to the DST execution units 6-8, where the still further storage unit information 682 includes the request to deactivate the DST execution units 6-8.

FIG. 48C is a flowchart illustrating an example of maintaining encoded data slice storage with regards to power utilization. The method includes step 690 where a processing module (e.g., of a distributed storage and task (DST) processing unit) selects a first subset of storage units of a set of storage units for temporary deactivation. The selecting includes at least one of a random selection, a predetermined selection, interpreting a request, interpreting a schedule, utilizing a round robin approach, and interpreting power utilization. When maintaining a write threshold number of encoded data slices of each set of encoded data slices, the processing module selects a width minus a write threshold number of storage units for the temporary deactivation.

The method continues at step 692 where the processing module facilitates deactivation of the first subset of storage units. For example, the processing module issues a deactivation request to the first subset of storage units. The method continues at step 694 where the processing module maintains a write threshold number of encoded data slices for each set of stored encoded data slices in remaining storage units of the set of storage units while the first subset of storage units are deactivated. For example, the processing module stores a write threshold number of encoded data slices when storing new data. As another example, the processing module only rebuilds to a write threshold number of encoded data slices of each set of encoded data slices when detecting a storage error.

Subsequent to storage of additional data in the remaining storage units, the method continues at step 696 where the processing module detects a storage imbalance between the remaining storage units and the deactivated storage units. For example, the processing module indicates the imbalance when a difference between a storage utilization level of the remaining storage units and a storage utilization level of the deactivated storage units is greater than a threshold level.

The method continues at step 698 where the processing module selects a second subset of storage units for temporary deactivation. The selecting includes selecting storage units that are different than the first subset of storage units. The method continues at step 700 where the processing module facilitates reactivation of the first subset of storage units. For example, the processing module issues a reactivation request to the first subset of storage units.

The method continues at step 702 where the processing module facilitates storage rebalancing by storing encoded data slices in the reactivated first subset of storage units. For example, the processing module transfer slices (e.g., those incrementally stored while the first subset was deactivated) from the second subset of storage units to the first subset of storage units. As another example, the processing module rebuilds missing encoded data slices associated with the first subset of storage units (e.g., those encoded data slices associated with data objects that were stored while the first subset of storage units where deactivated). As yet another example, the processing module stores new encoded data slices associated with the first subset of storage units. The method continues at step 704 where the processing module facilitates deactivation of the second subset of storage units. For example, the processing module issues a deactivation request to the second subset of storage units.

FIG. 49A is a schematic block diagram of another embodiment of a dispersed storage network (DSN) that includes the distributed storage and task (DST) processing unit 16 of FIG. 1, the network 24 of FIG. 1, and a DST execution (EX) unit set 710. The DST execution unit set 710 includes a set of DST execution units 1-n. Each DST execution unit includes the processing module 84 of FIG. 3 and the memory 88 of FIG. 3. Each DST execution unit may be implemented utilizing the DST execution unit 36 of FIG. 1. Hereafter, each DST execution unit may be interchangeably referred to as a storage unit and the DST execution unit set may be interchangeably referred to as a storage unit set or as a set of storage units. The DSN functions to coordinate task execution amongst a set of DST execution units.

In an example of operation of the coordinating of the task execution, a storage unit determines current performance information for two or more storage units of the set of storage units, where the performance information includes one or more of slice access latency levels (e.g., time from start of issuing a slice access request 714 from the DST processing unit 16 to receiving a corresponding slice access response 716 by the DST processing unit 16), and slice access throughput levels. The determining includes at least one of the storage units exchanging status information 712 that includes the performance information, interpreting a query response, interpreting a test result, and interpreting an error message. For example, the processing module 84 of the DST execution unit 1 exchanges the status information 712 with DST execution units 2-n.

Having determined the current performance information, the storage unit determines desired performance information for the two or more storage units. The determining includes at least one of interpreting system registry information, adapting a dynamic metric, interpreting a historical record, and interpreting a received request. Having determined the desired performance information, the storage unit identifies pending tasks associated with the two or more storage units. For example, the storage units access tasks in their memory 88 and exchange status information between each other, where the status information includes the identification of the pending tasks.

Having identified the pending tasks, the storage unit determines an approach level based on the current performance, the desired performance information, and the identified pending tasks. The approach level includes a metric on a continuum of approaches that balances optimization of latency at one extreme and optimization of throughput at the other extreme. The determining includes at least one of performing a lookup and calculating based on a deterministic function (e.g., weight throughput higher when the pending tasks include archiving data, weight latency higher when the tasks are more transactional in nature).

Having determined the approach level, the storage unit determines a sequence of steps to facilitate execution of the pending tasks based on the approach level, where the sequence of steps includes individual actions optimized in accordance with the approach level. The determining includes at least one of performing a lookup, interpreting historical records to identify a previous sequence of steps associated with successful matching of desired performance and current performance for previous tasks that compare favorably to the pending tasks (e.g., rearranging order of memory access to cluster similar access steps within a timeframe), and associating time frames with similar steps across the set of storage units to provide similar performance to the DST processing unit 16.

Having determined the sequence of steps, the storage units exchange status information 712 that includes one or more of the approach level, the determine sequence of steps, the identified pending task, and the desired performance level. Having exchanged the status information, the storage units facilitate execution of the determined sequence of steps.

FIG. 49B is a flowchart illustrating an example of coordinating task execution amongst a set of storage units. The method includes step 720 where a processing module (e.g., of a storage unit) determines current performance information for two or more storage units of a set of storage units that includes the storage unit. The determining includes one or more of interpreting a test result, interpreting a query response, interpreting an error message, and exchange information with other storage units.

The method continues at step 722 where the processing module determines desired performance information for the two or more storage units. The determining includes at least one of interpreting system registry information, updating previous desired performance information, interpreting a historical record, and interpreting a received request. The method continues at step 724 where the processing module identifies pending tasks associated with the two or more storage units. For example, the processing module retrieves the pending tasks from a local memory. As another example, the processing module receives the pending tasks from another storage unit.

The method continues at step 726 where the processing module determines an approach level based on the current performance information, the desired performance information, and the pending tasks. For example, the processing module calculates the approach level using a deterministic function. As another example, the processing module performs a lookup.

The method continues at step 728 where the processing module determines a sequence of steps to facilitate execution of the pending tasks based on the approach level. The determining includes at least one of identifying a previous template the compares favorably to the pending tasks, performing a lookup, and interpreting a historical record. The method continues at step 730 where two or more storage units facilitate execution of the determined sequence of steps. For example, the two or more storage units exchange the sequence of steps and synchronize execution of sequence of steps amongst a set of storage units.

As may be used herein, the terms “substantially” and “approximately” provides an industry-accepted tolerance for its corresponding term and/or relativity between items. Such an industry-accepted tolerance ranges from less than one percent to fifty percent and corresponds to, but is not limited to, component values, integrated circuit process variations, temperature variations, rise and fall times, and/or thermal noise. Such relativity between items ranges from a difference of a few percent to magnitude differences. As may also be used herein, the term(s) “operably coupled to”, “coupled to”, and/or “coupling” includes direct coupling between items and/or indirect coupling between items via an intervening item (e.g., an item includes, but is not limited to, a component, an element, a circuit, and/or a module) where, for indirect coupling, the intervening item does not modify the information of a signal but may adjust its current level, voltage level, and/or power level. As may further be used herein, inferred coupling (i.e., where one element is coupled to another element by inference) includes direct and indirect coupling between two items in the same manner as “coupled to”. As may even further be used herein, the term “operable to” or “operably coupled to” indicates that an item includes one or more of power connections, input(s), output(s), etc., to perform, when activated, one or more its corresponding functions and may further include inferred coupling to one or more other items. As may still further be used herein, the term “associated with”, includes direct and/or indirect coupling of separate items and/or one item being embedded within another item. As may be used herein, the term “compares favorably”, indicates that a comparison between two or more items, signals, etc., provides a desired relationship. For example, when the desired relationship is that signal 1 has a greater magnitude than signal 2, a favorable comparison may be achieved when the magnitude of signal 1 is greater than that of signal 2 or when the magnitude of signal 2 is less than that of signal 1.

As may also be used herein, the terms “processing module”, “processing circuit”, and/or “processing unit” may be a single processing device or a plurality of processing devices. Such a processing device may be a microprocessor, micro-controller, digital signal processor, microcomputer, central processing unit, field programmable gate array, programmable logic device, state machine, logic circuitry, analog circuitry, digital circuitry, and/or any device that manipulates signals (analog and/or digital) based on hard coding of the circuitry and/or operational instructions. The processing module, module, processing circuit, and/or processing unit may be, or further include, memory and/or an integrated memory element, which may be a single memory device, a plurality of memory devices, and/or embedded circuitry of another processing module, module, processing circuit, and/or processing unit. Such a memory device may be a read-only memory, random access memory, volatile memory, non-volatile memory, static memory, dynamic memory, flash memory, cache memory, and/or any device that stores digital information. Note that if the processing module, module, processing circuit, and/or processing unit includes more than one processing device, the processing devices may be centrally located (e.g., directly coupled together via a wired and/or wireless bus structure) or may be distributedly located (e.g., cloud computing via indirect coupling via a local area network and/or a wide area network). Further note that if the processing module, module, processing circuit, and/or processing unit implements one or more of its functions via a state machine, analog circuitry, digital circuitry, and/or logic circuitry, the memory and/or memory element storing the corresponding operational instructions may be embedded within, or external to, the circuitry comprising the state machine, analog circuitry, digital circuitry, and/or logic circuitry. Still further note that, the memory element may store, and the processing module, module, processing circuit, and/or processing unit executes, hard coded and/or operational instructions corresponding to at least some of the steps and/or functions illustrated in one or more of the Figures. Such a memory device or memory element can be included in an article of manufacture.

The present invention has been described above with the aid of method steps illustrating the performance of specified functions and relationships thereof. The boundaries and sequence of these functional building blocks and method steps have been arbitrarily defined herein for convenience of description. Alternate boundaries and sequences can be defined so long as the specified functions and relationships are appropriately performed. Any such alternate boundaries or sequences are thus within the scope and spirit of the claimed invention. Further, the boundaries of these functional building blocks have been arbitrarily defined for convenience of description. Alternate boundaries could be defined as long as the certain significant functions are appropriately performed. Similarly, flow diagram blocks may also have been arbitrarily defined herein to illustrate certain significant functionality. To the extent used, the flow diagram block boundaries and sequence could have been defined otherwise and still perform the certain significant functionality. Such alternate definitions of both functional building blocks and flow diagram blocks and sequences are thus within the scope and spirit of the claimed invention. One of average skill in the art will also recognize that the functional building blocks, and other illustrative blocks, modules and components herein, can be implemented as illustrated or by discrete components, application specific integrated circuits, processors executing appropriate software and the like or any combination thereof.

The present invention may have also been described, at least in part, in terms of one or more embodiments. An embodiment of the present invention is used herein to illustrate the present invention, an aspect thereof, a feature thereof, a concept thereof, and/or an example thereof. A physical embodiment of an apparatus, an article of manufacture, a machine, and/or of a process that embodies the present invention may include one or more of the aspects, features, concepts, examples, etc., described with reference to one or more of the embodiments discussed herein. Further, from figure to figure, the embodiments may incorporate the same or similarly named functions, steps, modules, etc., that may use the same or different reference numbers and, as such, the functions, steps, modules, etc., may be the same or similar functions, steps, modules, etc., or different ones.

While the transistors in the above described figure(s) is/are shown as field effect transistors (FETs), as one of ordinary skill in the art will appreciate, the transistors may be implemented using any type of transistor structure including, but not limited to, bipolar, metal oxide semiconductor field effect transistors (MOSFET), N-well transistors, P-well transistors, enhancement mode, depletion mode, and zero voltage threshold (VT) transistors.

Unless specifically stated to the contra, signals to, from, and/or between elements in a figure of any of the figures presented herein may be analog or digital, continuous time or discrete time, and single-ended or differential. For instance, if a signal path is shown as a single-ended path, it also represents a differential signal path. Similarly, if a signal path is shown as a differential path, it also represents a single-ended signal path. While one or more particular architectures are described herein, other architectures can likewise be implemented that use one or more data buses not expressly shown, direct connectivity between elements, and/or indirect coupling between other elements as recognized by one of average skill in the art.

The term “module” is used in the description of the various embodiments of the present invention. A module includes a processing module, a functional block, hardware, and/or software stored on memory for performing one or more functions as may be described herein. Note that, if the module is implemented via hardware, the hardware may operate independently and/or in conjunction software and/or firmware. As used herein, a module may contain one or more sub-modules, each of which may be one or more modules.

While particular combinations of various functions and features of the present invention have been expressly described herein, other combinations of these features and functions are likewise possible. The present invention is not limited by the particular examples disclosed herein and expressly incorporates these other combinations. 

What is claimed is:
 1. A method for execution by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), the method comprises: receiving, from a requesting device, a request to retrieve a unique copy of a data file from a centralized storage system, wherein the centralized storage system stores the data file as a plurality of sets of encoded data slices, wherein the data file is divided into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed storage error encoded to produce a set of encoded data slices of the plurality of sets of encoded data slices, wherein a decode threshold number of encoded data slices of the set of encoded data slices is needed to recover the data segment, and wherein the plurality of sets of encoded data slices is stored in a set of storage units of the DSN; determining a retrieval combination code from the request for the requesting device; interpreting the retrieval combination code to identify a sub-set of storage units of the set of storage units, wherein a number of storage units in the sub-set of storage units equals the decode threshold number; sending read requests to the sub-set of storage units regarding the decode threshold number of encoded data slices; and when the decode threshold number of encoded data slices is received, decoding the decode threshold number of encoded data slices to recover the data segment.
 2. The method of claim 1 further comprises: providing the recovered data segment to the requesting device.
 3. The method of claim 1, wherein the interpreting the retrieval combination code comprises: converting the retrieval combination code into a binary number, wherein the binary number includes a number of bit positions and wherein the decode threshold number of the number of bit positions includes a one and a remaining number of the number of bit positions includes a zero; and interpreting the binary number to identify the sub-set of storage units.
 4. The method of claim 3 further comprises: the number of bit positions equals a number of storage units in the set of storage units; and the interpreting the binary number further includes identifying the sub-set of storage units based on bit positions of the number of bit positions including a one.
 5. The method of claim 1, wherein the determining the retrieval combination code comprises: determining a group of combination request values from the request and based on identity of the requesting device; selecting one of the combination request values from the group of combination request values; and utilizing the selected combination request value as the retrieval combination code.
 6. The method of claim 1 further comprises: when the decode threshold number of encoded data slices is not received: identifying storage units of the sub-set of storage units for which an encoded data slice of the decode threshold number of encoded data slices was successfully received; generating a partial retrieval combination code based on the identity of the storage units of the sub-set of storage units for which the encoded data slice was successfully received; determining an alternate retrieval combination code that approximates the partial retrieval combination code and conforms to the retrieval combination code of the requesting device; interpreting the alternate retrieval combination code to identify another storage unit of the set of storage units to retrieve another encoded data slice of the set of encoded data slices; and sending a retrieval request to the other storage unit regarding the other encoded data slice.
 7. A non-transitory computer readable storage medium comprises: at least one memory section that stores operational instructions that, when executed by one or more processing modules of one or more computing devices of a dispersed storage network (DSN), causes the one or more computing devices to: receive, from a requesting device, a request to retrieve a unique copy of a data file from a centralized storage system, wherein the centralized storage system stores the data file as a plurality of sets of encoded data slices, wherein the data file is divided into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed storage error encoded to produce a set of encoded data slices of the plurality of sets of encoded data slices, wherein a decode threshold number of encoded data slices of the set of encoded data slices is needed to recover the data segment, and wherein the plurality of sets of encoded data slices is stored in a set of storage units of the DSN; determine a retrieval combination code from the request for the requesting device; interpret the retrieval combination code to identify a sub-set of storage units of the set of storage units, wherein a number of storage units in the sub-set of storage units equals the decode threshold number; send read requests to the sub-set of storage units regarding the decode threshold number of encoded data slices; and when the decode threshold number of encoded data slices is received, decode the decode threshold number of encoded data slices to recover the data segment.
 8. The non-transitory computer readable storage medium of claim 7 further comprises: the at least one memory section stores further operational instructions that, when executed by the one or more processing modules, causes the one or more computing devices of the DSN to: provide the recovered data segment to the requesting device.
 9. The non-transitory computer readable storage medium of claim 7, wherein the one or more processing modules functions to execute the operational instructions stored by the at least one memory section to cause the one or more computing devices of the DSN to interpret the retrieval combination code by: converting the retrieval combination code into a binary number, wherein the binary number includes a number of bit positions and wherein the decode threshold number of the number of bit positions includes a one and a remaining number of the number of bit positions includes a zero; and interpreting the binary number to identify the sub-set of storage units.
 10. The non-transitory computer readable storage medium of claim 9, wherein the one or more processing modules functions to execute the operational instructions stored by the at least one memory section to cause the one or more computing devices of the DSN to interpret the binary number by: the number of bit positions equals a number of storage units in the set of storage units; and identifying the sub-set of storage units based on bit positions of the number of bit positions including a one.
 11. The non-transitory computer readable storage medium of claim 7, wherein the one or more processing modules functions to execute the operational instructions stored by the at least one memory section to cause the one or more computing devices of the DSN to determine the retrieval combination code by: determining a group of combination request values from the request and based on identity of the requesting device; selecting one of the combination request values from the group of combination request values; and utilizing the selected combination request value as the retrieval combination code.
 12. The non-transitory computer readable storage medium of claim 7 further comprises: the at least one memory section stores further operational instructions that, when executed by the one or more processing modules, causes the one or more computing devices of the DSN to: when the decode threshold number of encoded data slices is not received: identify storage units of the sub-set of storage units for which an encoded data slice of the decode threshold number of encoded data slices was successfully received; generate a partial retrieval combination code based on the identity of the storage units of the sub-set of storage units for which the encoded data slice was successfully received; determine an alternate retrieval combination code that approximates the partial retrieval combination code and conforms to the retrieval combination code of the requesting device; interpret the alternate retrieval combination code to identify another storage unit of the set of storage units to retrieve another encoded data slice of the set of encoded data slices; and send a retrieval request to the other storage unit regarding the other encoded data slice.
 13. A computing device of a group of computing devices of a dispersed storage network (DSN), the computing device comprises: an interface; a local memory; and a processing module operably coupled to the interface and the local memory, wherein the processing module functions to: receive, from a requesting device, a request to retrieve a unique copy of a data file from a centralized storage system, wherein the centralized storage system stores the data file as a plurality of sets of encoded data slices, wherein the data file is divided into a plurality of data segments, wherein a data segment of the plurality of data segments is dispersed storage error encoded to produce a set of encoded data slices of the plurality of sets of encoded data slices, wherein a decode threshold number of encoded data slices of the set of encoded data slices is needed to recover the data segment, and wherein the plurality of sets of encoded data slices is stored in a set of storage units of the DSN; determine a retrieval combination code from the request for the requesting device; interpret the retrieval combination code to identify a sub-set of storage units of the set of storage units, wherein a number of storage units in the sub-set of storage units equals the decode threshold number; send read requests to the sub-set of storage units regarding the decode threshold number of encoded data slices; and when the decode threshold number of encoded data slices is received, decode the decode threshold number of encoded data slices to recover the data segment.
 14. The computing device of claim 13, wherein the processing module further functions to: provide the recovered data segment to the requesting device.
 15. The computing device of claim 13, wherein the processing module functions to interpret the retrieval combination code by: converting the retrieval combination code into a binary number, wherein the binary number includes a number of bit positions and wherein the decode threshold number of the number of bit positions includes a one and a remaining number of the number of bit positions includes a zero; and interpreting the binary number to identify the sub-set of storage units.
 16. The computing device of claim 15, wherein the processing module functions to interpret the binary number by: the number of bit positions equals a number of storage units in the set of storage units; and identifying the sub-set of storage units based on bit positions of the number of bit positions including a one.
 17. The computing device of claim 13, wherein the processing module functions to determine the retrieval combination code by: determining a group of combination request values from the request and based on identity of the requesting device; selecting one of the combination request values from the group of combination request values; and utilizing the selected combination request value as the retrieval combination code.
 18. The computing device of claim 13, wherein the processing module further functions to: when the decode threshold number of encoded data slices is not received: identify storage units of the sub-set of storage units for which an encoded data slice of the decode threshold number of encoded data slices was successfully received; generate a partial retrieval combination code based on the identity of the storage units of the sub-set of storage units for which the encoded data slice was successfully received; determine an alternate retrieval combination code that approximates the partial retrieval combination code and conforms to the retrieval combination code of the requesting device; interpret the alternate retrieval combination code to identify another storage unit of the set of storage units to retrieve another encoded data slice of the set of encoded data slices; and send a retrieval request to the other storage unit regarding the other encoded data slice. 